Bug 939174 - Launch whats new FTU tutorial to demo edge gestures etc. r=borjasalguero,alive

* Add shared VersionHelper
* Unit tests for VersionHelper, FTULauncher
* Check device.previous_os in FTULauncher/FTU app
* Launch full ftu when ftu.enabled always
* Launch ftu whats new tutorial when upgrade detected
* Add config for 1.3-2.0 upgrade tutorial
Merge pull request #20175 from davidflanagan/bug995540-master

Merge pull request #19409 from dmarcos/bug995540 r=dmarcos
Merge pull request #20087 from sfoster/bug-939174-upgrade-tutorial

Bug 939174 - Launch whats new FTU tutorial to demo edge gestures etc. r=borjasalguero,alive
Bug 1020435 - One word fix to finalize FTU tutorial strings
Merge pull request #20111 from sfoster/bug-1020435-strings

Bug 1020435 - 'Hold an' not 'Hold on an' icon in new FTU strings. r=fcampo
Bug 1009633 - Pre-polulate browser top sites by SIM
Bug 1019289 - Final FTE videos from epang, with 1x, 1.5x and 2x resolutions. r=fcampo
Merge pull request #19559 from acperez/bug-1009633

Bug 1009633 - Pre-polulate browser top sites by SIM
Merge pull request #20107 from sfoster/bug-1019289-videos

Bug 1019289 - Final FTE videos from epang, with 1x, 1.5x and 2x res. r=fcampo
Merge pull request #20116 from etiennesegonzac/bug-1021237

Bug 1021237 - Make the edge zones higher in landscape mode. r=21
Merge pull request #20120 from etiennesegonzac/bug-1021533

Bug 1021533 - (bug 1018836 follow up) css class cleanup. r=alive
Bug 1000895 - Clean up bootstrap mozL10n API use in System. r=alive
Merge pull request #20011 from borjasalguero/mobileid_ui

Bug 1003330: Mobile identity UI. r=ferjm
Bug 1022131 - Intermittent Marionette JS Failure on Travis: Statusbar Scrolling > The statusbar changes the appearance properly
Bug 1014043 - Conform call_log_test.js to jshint

I also refreshed the xfail.list
Bug 1014043 - Check the active SIM card before calling in call log
Bug 983812 - Center header text based on amount of available space
Bug 1018698 - Create gaia-radio web component r=arnau
Merge pull request #19853 from KevinGrandon/bug_1018698_create_gaia_radio

Bug 1018698 - Create gaia-radio web component
Merge pull request #18680 from stasm/1000895-system-once-ready

Bug 1000895 - Clean up bootstrap mozL10n API use in System. r=alive