Bug 1020109 - Cell broadcast search list is not set correctly

The current code attempts to protect against empty objects incorrectly
since empty arrays are truthy in JavaScript. The result is empty objects
get passed to SettingsLock.set() which seems to break all subsequent
settings change observers.
Bug 996510 - Add system message test case for Bug 906164
Bug 991949 - Cell broadcast ETWS messages show undefined

ETWS messages without a message body use a canned body depending on the
warning type.

Change-Id: I25491fd85894d334bd6a9ab63105379de495ef2a
Bug 1021777 - Set multiple search engines by default
Bug 1022450 - Don't show the "WAP Push Message" string in the header when opening a message
Bug 1023053 - [Calendar] Clean up useless images
Bug 1022733 - Entry points lost their splash screen/overlay icons

The origin for applications that have different entry points (e.g.,
Dialer and Contacts are the same application, Communications) also
contains a pathname, so we need to remove that from the origin before
appending the splash icon path.
Bug 1020005: Send 'shrinking-stop' instead of 'shrinking-reject' event whenever 'techLost' event happens.
Also modified respective test case in nfc_manager_test.js. r=gweng
Bug 876815 -[usage] don't mention phone calls in settings sub-header
Bug 1023989 - fixed roles and labels for e.me's collection/search results view.
Bug 1023996 - adding missing aria attributes to e.me controls.
Bug 1022781 - Remove unnecessary plural form in Conference Call header
Bug 984340 - Enable sdcard tests on desktop B2G. r=bsilverberg
Bug972573, The selection screen for adding a contact with multiple phone numbers to a SMS message lacks a cancel, back, or 'x' button
Bug 1021732 - Update test_privileged_app_contacts_prompt to match new prompt behaviour
Bug 1024516 - Update test_privileged_app_audio_prompt and video_prompt to match new prompt behaviour
Bug 1018214 - adding a number of gaia ui tests for status bar and utility tray accessibility. r=Bebe
Bug 1021710 - updating accessibility.js to use standard marionette timeout instead of it's arbitrary one when retrieving an accessible object.
Bug 1024652 - commented out part of the test_a11y_phone_call_log test that tests contact action menu until long press is supported.
Bug 1023198 - Sort Gu tests after os.walk for determinism, jgriffin