Added UndoBar to build.gradle - https://github.com/soarcn/UndoBar
Added dropdown arrow drawable
Basic logic has been implemented w/o API call (since it doesn't exist yet)
Changed undo text, now remembering tapped post before blocking blog
API calls to block/unblock are now coded (untested)
Reworded undo text
Rewrote ReaderAnim.animateListItem() to use predefined styles
Added comment header
Merge branch 'develop' of https://github.com/wordpress-mobile/WordPress-Android into issue/1491-reader-block-blog

Conflicts:
	build.gradle
Merge branch 'develop' of https://github.com/wordpress-mobile/WordPress-Android into issue/1491-reader-block-blog
Added ActionListener to block/unblock blog
Added missing hasActivity()
Changed blocking animation
Changed blocking animation (again) and now removing list item after blocking
Increased padding around dropdown icon
Changed to using a PopupMenu
Merge branch 'develop' of https://github.com/wordpress-mobile/WordPress-Android into issue/1491-reader-block-blog
Added logging, changed checkBlogUrlReachable to use HEAD request
Changed error message when blocking fails
Changed popup menu style