Add some style to step view and edit

Added a light gray background behind the step media container so images with
white backgrounds don't get washed out.  Also fixed some padding/spacing issues
with thumbnails.
Convert janky relativelayout border to drawable
Step view/edit phone screen size tweaks
Fix step line voice dictation.

onActivityResult was calling through to the wrong fragments onActivityResult
sporatically, causing it to look like speech to text wasn't working.  Instead
of calling through to the fragments onActivityResult, instead just fire off an
otto event from StepEditActivity's onActivityResult.
The discard icon looks identical to back, always stick it in overflow
No need to invalidate the pager since we just recreated it