Show file status in change details file list

Colour file paths by status (green: added, red: removed)
Mark files as binary if so
Don't show lines inserted/deleted if there weren't any lines
 inserted/deleted
Disable the onClick listener for binary files - there will be no
 diff available regardless.
Use an enum to store the file status in FileInfo
GerritControllerActivity: Added some null checking
PatchSetChangesCard: Removed some dead code
JSONCommit: Convert reviewers getters to List
ReviewerList: Add method to get all labels reviewers are associated with

Change-Id: I9308fdcb58d588ba340618b5280b573f98301d44