Bug 969101: Initial implementation of a first-time use ping. r=fabrice
 Bug 971459 - [System2] Instantiable Applications.
Bug 988848 - Documentation for gaia-marionette is wrong. r=21
Merge pull request #17639 from mpizza/Bug_971459_landed_IN_master

 Bug 971459 - [System2] Instantiable Applications. r=alive.
Bug 987946 - [unittest] test_cold_launch.py failing

The test is failing because the correct app url is now not available until
shortly after launching.
This patch changes the test so it waits for the correct app url, rather than
just immediately asserting that it is as expected.
Merge pull request #17604 from bobsilverberg/cold_launch

Bug 987946 - [unittest] test_cold_launch.py failing
Revert "Merge pull request #17576 from Rik/sms-send-button-907103"

This reverts commit a3d4a9e35c5e5f25d4ab6035aebf422f09938688, reversing
changes made to 24f53ad7eb48c6e773413687fa76c81983f926f3.
Bug 971459 - [System2] Instantiable Applications r=me
Revert "Bug 982033 - change layout manager instantiate place to solve app_window dependency" to resolve test bustage

This reverts commit 5b499bc5ffbc4fe62d90154dc0d3233bcf30ddd0.
Merge pull request #17673 from marshall/ftuPing

Bug 969101: Initial implementation of a first-time use ping.
Bug 948263 - [User Story] Warning when the battery is low while recording a video