Bug 957122 - Enable more TBPL tests - Messages app

Enable test_sms_add_contact and test_sms_to_settings on TBPL
Bug 949801 - [B2G][MMS] Service currently unavailable is prompted when deleting a MMS that is in the process of being sent r=julienw

Fix indentation.
Bug 957122 - Enable more TBPL tests - Unit tests

Enable test_prefs on TBPL
Bug 948847 - [Gaia] add AirplaneModeHelper

- other apps can use AirplaneModeHelper to know current airplane status
- add a lot of related unit tests
- add two mozSettings key for airplane mode use
- update gaia-ui-tests
Bug 959659 - Fix an issue that prevented the last file in a directory from being recompressed
Bug 959659 - Recompress all the PNG assets of the bluetooth app
Bug 959659 - Recompress all the PNG assets of the browser app
Bug 959659 - Recompress all the PNG assets of the calendar app
Bug 959659 - Recompress all the PNG assets of the camera app
Bug 959659 - Recompress all the PNG assets of the clock app
Bug 959659 - Recompress all the PNG assets of the communications apps
Bug 959659 - Recompress all the PNG assets of the costcontrol app
Bug 959659 - Recompress all the PNG assets of the email app
Bug 959659 - Recompress all the PNG assets of the fm app
Bug 959659 - Recompress all the PNG assets of the gallery app
Bug 959659 - Recompress all the PNG assets of the homescreen app
Bug 959659 - Recompress all the PNG assets of the keyboard app
Bug 959659 - Recompress all the PNG assets of the music app
Bug 959659 - Recompress all the PNG assets of the pdfjs app
Bug 959659 - Recompress all the PNG assets of the search app