• "Allow one new tab" button at the bottom of the settings,
  for allowing tabs from realy need it without disabling the extension.
  Useful for pages like about:debugging, print previews, and OAuth.
  Nice to avoid forgetting to re-enable the extension later.

Behavior is as follows:
- After a single button press, let a single tab through that would otherwise be blocked.
- Presses stack: three taps will allow three blocked tabs to subsequently open.
- Only tabs that would be blocked count.
- No expiry. A slow page load or a slow / distracted user shouldn't be
inconvenienced.
- Placed at the bottom, deliberately plain. It is an escape hatch, and should
be reachable without being the first thing your thumb finds.

• Removed unused CSS left over from a development build.
• Icon updated with brighter arrow for higher visibility at low resolutions.

• The unblocked tab grace count is stored as { n, until }, with a null field meaning "no bound". "Pause for 10 minutes" would be { n: null, until: <timestamp> }and
  needs no change to the code that implements the tab grace count/period.

• Icon updated with wider arrow for higher visibility at low resolutions.

• Desktop ceiling is now off by default. Click "Limit open tabs above ceiling" to enable.
• Desktop tab ceiling threshold is now displayed and can be changed even when ceiling is disabled. We hope that by displaying it we can reduce new user confusion and surprise.

• Android detects when a tab is supposed to close on page load and now force-closes the tab.
  This fixes the problem with the "+" tab (about:blank), which cannot be force-closed.

• This version customizes the interfaces for Android and Desktop,
  because there is no way to read the actual number of tabs on Android.

• "Limit open tabs" is now a standalone toggle on Desktop, allowing the tab limit to be disabled without changing its value.
• "Block new tabs" is now a standalone toggle on Android.
• Android provides number of tabs opened and closed in the last hour, in lieu of an absolute tab count.
• Android interface now shows if the circuit breaker has been hit.
• Android adds a classifier for loading tabs based on their dimensions.

• The interface is now platform-dependent: a master toggle and a ceiling setter are shown on Desktop,
  but a master toggle and count of opened and closed tabs is shown on Android.
• The tab ceiling interface has been removed from Android, in favor of a "block tabs" toggle.
  A numerical ceiling doesn't make sense where we can't know the absolute number of tabs.
• On Desktop, the tab ceiling is no longer capped at 30, and the interface allows typing in numbers.
• The arrow buttons used to set the tab ceiling now scale their increment with the current tab ceiling setting.
• The row of pips now hides itself above 30 tabs / pips.

• Tab opening detection on Android is now experimentally verified.
  It only counts (and blocks) tabs which are newly opened by the user (as opposed to loaded from an inactive tab).
• Platform detection was previously dependent on successfully reading and counting the open tabs,
  which would prevent the interface from showing if the counting errored out. Now independent.

• Tab opening detection on Android fails if user uses the "+" button.
• Unchecking "Limit Open Tabs" on Desktop hides the ceiling. Would be better if ceiling were greyed out.

This version attempted to implement the features listed in the 1.5.0 changelog.
However, mismatching files were deployed resulting in a broken extension.

• This version splits the interfaces between Android and Desktop,
  because there is no way to read the actual number of tabs on Android.

• "Limit open tabs" is now a standalone toggle on Desktop, allowing the tab limit to be disabled without changing its value.
  It is on by default.
• "Block new tabs" is now a standalone toggle on Android.
• Android provides number of tabs opened and closed in the last hour, in lieu of an absolute tab count.
• Android interface now shows if the circuit breaker has been hit.

• The interface is now platform-dependent: a master toggle and a ceiling setter are shown on Desktop,
  but a master toggle and count of opened and closed tabs is shown on Android.
• The tab ceiling interface has been removed from Android, in favor of a "block tabs" toggle.
  A numerical ceiling doesn't make sense where we can't know the absolute number of tabs.
• On Desktop, the tab ceiling is no longer capped at 30, and the interface allows typing in numbers.
• The arrow buttons used to set the tab ceiling now scale their increment with the current tab ceiling setting.
• The row of pips now hides itself above 30 tabs or pips.

• Tab opening detection on Android is now experimentally verified.
  It only counts (and blocks) tabs which are newly opened by the user (as opposed to loaded from an inactive tab).
• Platform detection was previously dependent on successfully reading and counting the open tabs,
  which would prevent the interface from showing if the counting errored out. Now independent.

• Disable the tab ceiling by stepping the counter limit past 30 tabs.
  In "Always" mode links are still collapsed into the current tab
  regardless of the counter setting.
• "Load links in the current tab" replaces the old on/off setting with three
  modes, defaulting to Never:
• Never: at the ceiling, a new tab is closed and its URL dropped. This
  preserves the state of the page you are currently reading.
• At ceiling: at the ceiling, the URL loads in the tab you tapped the
  link from instead of being dropped. Under the ceiling, links open new tabs
  normally.
• Always: links never open new tabs.

• target="_blank" links are now only rewritten into the current tab in
  "Always" mode. Previously they were rewritten at every tab count regardless
  of the setting.
• Settings from earlier versions are migrated on first run.
  This affects exactly one user.
• Rewrote the add-on description.

• Removed tab counting dependence on windowId. Firefox for Android has no
  window concept. Tabs are now matched on their private-browsing flag.
• The popup now shows an error in place of the tab count when it can't read
  tabs, rather than sitting on placeholder dashes.
• build.sh creates build/ if it's missing, and replaces the archive instead
  of appending to it. Deleted files could previously survive in later builds.

Change log, v1.1.1:

• Rename popup item from "Open blocked links here" to "Open blocked links in origin tab".
• Disable the above setting by default to avoid ruining reader's state.
• Modify tab counting code to remove dependence on "Window" to try to get it to work on Android.
• Tested on FF desktop but not on Android yet.