Fix for bug 969996

Delay chunk rendering by grouping chunks into larger
sets before calling renderChunk.  First set size will
be the same as the current FIRST_CHUNK_SIZE (6).  Subsequent
sets will cap at INCREMENTAL_RENDER_SIZE (60).

The goal is to reduce reflows on rendering the call log.

Also fixed the following bugs:
  _groupCounter never gets incremented if there's only one log entry per day
  Change currDate and prevDate comparison to more readable form

Added unit tests for call log rendering of various sizes.
Bug 971625 - [settings] refactor marionette test for support panel
[DSDS][Gaia][Sim Manager] support always ask feature

- add 'always ask' option
- add related unit test
Bug 957100 - [Settings] add marionette for b2g-improve and feedback page
Bug 903134 - Clean up Trusted UI on mozbrowsererror, mozbrowserclose
Bug 975963 - Split keyboard.js into instancable KeyboardApp() and boot.js
Bug 976022 - Intermittent test_clock_delete_alarm.TestClockDeleteAlarm
Merge pull request #16107 from yor-mozilla-com/fix969996

Fix for bug 969996 r=rik
Bug 969413 - Make the edit mode bottom margin rule apply only to the relevant elements r=julienw
Merge pull request #11816 from jedp/903134-mozbrowsererror

Bug 903134 - Clean up Trusted UI on mozbrowsererror; r=ferjm
Merge pull request #16567 from AndreiH/bug_976022

Bug 976022 - Intermittent test_clock_delete_alarm.TestClockDeleteAlarm
Revert "Update DM Strings r=kaze, arcturus" for causing gaia-unit test failures

This reverts commit 1e6949eaea6cb23be1de5955fc6b0827af7b40f0.
Bug 976124 - Python update clock/alarm locator for edit panel
Revert "Bug 975992 - Keep keyboard2 state in Gecko rather than Gaia"

This reverts commit 5ffd3aefddeb628ff27405e6d07281b108b5dec9.
Merge pull request #16575 from comoyo/revert_new_keyboard_promisify

Revert "Bug 975992 - Keep keyboard2 state in Gecko rather than Gaia"
Bug 974897 - Create local blacklist, build all apps for test-integration. r=gaye
Bug 972514 - [B2G][Email] ActiveSync message state changes from server not synchronized error "Failed to parse a message: Error: Bad body type: undefined" thrown. r=mcav
Merge pull request #16585 from asutherland/email-asflagfix

Bug 972514 - [B2G][Email] ActiveSync message state changes from server not synchronized error "Failed to parse a message: Error: Bad body type: undefined" thrown. r=mcav
Merge pull request #16243 from EragonJ/bug-972150

Bug 972150 -[DSDS][Gaia][Sim Manager] support always ask feature
Merge pull request #15459 from cctuan/957100

Bug 957100 - [Settings] add marionette for b2g-improve and feedback page r=crh0716