phabrinter per arai_a

An extension to make Phabricator (phabricator.services.mozilla.com instance) usability more similar to Splinter.

This provides the following feature:

• Clicking each "Path" in "Files" list shows only that file
• Clicking "All Files" in "Files" list shows all files
• "Reviewed" checkbox is added to each file, and that state is saved across reloads (expires in 30 days)
• Collapsed state ("[-]" button) is added to each file, and that state is saved across reloads (expires in 30 days)
  • This is different than Phabricator's built-in collapsed state
• Add collapse button ("[-]" button) to file list, to make the file list similar to Splinter
• (NEW in ver.0.5) Add "Show context" button to each comment summary, to show the context about the code and the previous comments, for each comment