Create a status bar item with a preliminary popover (menu player)
 Mergeable commit
Merge branch 'master' into status-bar

* master:
  Allow dragging of the application bar in the OS X theme. Fixes #20.
  Set window delegate to AppDelegate (handle window closing)
  Issue #15 Rev#2
  Apply navigation styles even when not applying OS X stylesheet
  Open links in the default browser. Fixes #19.
  Replace Google Play logo with back and forward buttons

Conflicts:
	google-music-mac.xcodeproj/project.pbxproj
	google-music-mac/AppDelegate.h
	google-music-mac/AppDelegate.m
Track playback, shuffle, repeat changes to update popover
Add thumbs up/down tracking and functionality to popover
Add menu icon

Icons per Ionicons.
Track and show playback time in popover
Show "No song currently playing"
Update playback slider view
Finalize popup (draw shadow, arrow, etc.)

Much thanks to https://github.com/shpakovski/Popup
Remove NSPopover artifacts
Restructure popup files
Update CSS for thumbs up/down. Fixes #34.
Update README with requirements. Fixes #38.
Update for version 1.0.3
Make popup transient (close when you interact with something else)
Add preference for menu popup; popup buttons refuse first responder
Merge branch 'master' into status-bar

* master:
  Update for version 1.0.3
  Update README with requirements. Fixes #38.
  Update CSS for thumbs up/down. Fixes #34.
Fix homepage link in README.md
Allow moving the playback slider from the popup