Bugs 951014, 987569, 989361: better orientation and transitions for preview gallery and pick confirmation views

don't register multiple resize handlers

restore the start and stop methods to lib/orientation.js

fix background color of preview gallery container

make swipe transition in preview gallery velocity sensitive

update tests

handle review comments

add code to remove resize listener in the confirm module
Merge pull request #18059 from davidflanagan/camera-preview

Bug 989361: better swipe handling for switching items in preview r=justindarc