Add indeterminate progress for refresh actions

Closes #198
Use static import for Window constant
Use standard refresh icon for action bar spinner
Add missing override annotation
Support navigating up from IssuesViewActivity

Closes #301
Add long click support to news feed

Closes #279
Don't open new activity when viewing yourself
Use a ViewFinder in CommitDiffListFragment
Show avatars in navigate to dialog
Support zooming out when viewing code

Closes #281
Closes #311
Add markdown processing of source code files

Closes #306
Closes #310
Update markdown extensions
Require '.' when checking markdown extensions
Import LoaderCallbacks directly
Hide progress when exception occurs
Add option to switch back to raw markdown

Markdown files are rendered by default when opened
but can still be toggled back to raw mode which is
saved as a preference.
Merge remote-tracking branch 'upstream/master'
Update app/res/values-fr/strings.xml

Closes #317
Fix "unassigned" in pt translation

Closes #325
Update Ukrainian locale

Closes #331