BUG 889164 updating slider whenever controls shown
Bug 853933 - Don't inline all locales as JSON in the HTML

Currently, in order to ensure that apps are translated before first paint, all l10n resources are included as one multi-locales JSON dictionary, which is serialized in an inline `<script>` element for each HTML document.  This works fine when shipping few locales, but it can increase the document size quite badly for 60+ locales, thus delaying the startup time very significantly.

This patch allows to support 60+ locales more easily by having:
* one minimal JSON dictionary per locale in each HTML file;
* one extensive JSON dictionary per locale in each webapp.

The inline JSON dictionary is split on a per-locale basis (= one `<script>` node per supported locale) and only contains the l10n strings that are required to translate the HTML document: the "startup cost" of each locale becomes neglectable, and it removes the risk of high RAM consumption when parsing a giant multi-locale JSON at startup.

All l10n resources that are not declared in the HTML document are concatenated in a single JSON dictionary per locale: this reduces the number of disk I/O to load l10n resources and does not increase the total disk size of each webapp.  To enable this, this patch implements a `{{locale}}` quasi-litteral in the HTML markup that is used to declare l10n resources:
  <link rel="prefetch" type="application/l10n" href="/{{locale}}.json" />
where `{{locale}}` is replaced by the value of `navigator.language`.

Note that this latter optimization is only interesting for apps that wait for the `localized` event to start. With the inline JSON dictionary for the declarative content and the `mozL10n.localize()` method, most apps could probably stop waiting for this `localized` event now.
 Bug 890176 - [Camera] Filmstrip preview opens even when video recording starts
Merge pull request #10709 from fabi1cazenave/l10nOptim-bug853933

Bug 853933 - Don't inline all locales as JSON in the HTML, r=ochameau
Bug 887737 - [SMS] The device is not recognizing the phone number received completely - r=julienw

* Rewrite the phone number matching regexp
* Include all the fixtures from Utils tests in FixturePhones and include in setup so we can share test cases
Bug 890232 - [Bluetooth File Transfer] The checked icon disappeared in paired devices selector.
Merge pull request #10797 from ian-liu/bluetooth/Bug890232_The_checked_icon_disappeared_in_paired_devices_selector

Bug 890232 - [Bluetooth File Transfer] The checked icon disappeared in paired devices selector., r=@rexboy7
Bug 881134 - hdpi/xhdpi resolution assets and layout for Bluetooth File Transfer app
Merge pull request #10789 from ian-liu/bluetooth/Bug881134_hdpi/xhdpi_resolution_assets_and_layout_for_Bluetooth_File_Transfer_app

Bug 881134 - hdpi/xhdpi resolution assets and layout for Bluetooth File Transfer app, r=@rexboy7
Bug 890216 - [Clock] The button of creating alarm is not align with displaying date/day context
Merge pull request #10796 from ian-liu/clock/Bug890216_creating_alarm_button_is_not_align_with_date/day_context

Bug 890216 - [Clock] The button of creating alarm is not align with displaying date/day context, r=@rexboy7
Bug 881139 - hdpi/xhdpi resolution assets and layout for Clock app
Merge pull request #10782 from ian-liu/clock/Bug881139_hdpi/xhdpi_resolution_assets_and_layout_for_Clock_app

Bug 881139 - hdpi/xhdpi resolution assets and layout for Clock app, r=@rexboy7
The save-bookmark screen does not work fine when Add to Home Screen button is pressed continuously
Merge pull request #10806 from crdlc/bug-890454

[Homescreen] The save-bookmark screen doesn't work fine when "Add to Home Screen" button is pressed continuously
Bug 883269 - [Contacts] Sort contacts in group when rendering the list. r=arcturus
Merge pull request #10764 from mcirlanaru/bug_883269

Bug 883269 - [Contacts] Sort contacts in group when rendering the list. r=@arcturus
Merge pull request #10785 from leob2g/bug_890176_filmstrip_preview_when_video_recording

 Bug 890176 - [Camera] Filmstrip preview opens even when video recording starts. r=daleharvey
Merge pull request #10761 from leob2g/bug_889164_update_slider_youtube_videos

BUG 889164 updating slider whenever controls shown. r=daleharvey
Revert "Merge pull request #10764 from mcirlanaru/bug_883269"

This reverts commit b068bef2bfbb759271d4446afa5d4b2207c44ae9, reversing
changes made to 7115b64f7dbf19a909ed8b75af94683903b0c118.