Bug 1063750 - Part 1: Replace Remote Tabs tray with messaging to Remote Tabs home panel. r=mcomella
Bug 1063750 - Part 2: Implement link from Remote Tabs tray to Remote Tabs home panel. r=mcomella

Deriving the correct panel UUID from the active Home Panel configuration
is challenging.  This is easy and will only exist for one release.  (The
Remote Tabs tray icon will disappear after this release; see Bug
1063753.)  This solves the problem in essentially all the situations we
expect to see.
Bug 1063750 - Part 3: Remove duplicated test-only PanelType. r=mcomella

Duplicate test types make it difficult to keep tests and code in
lock-step.  (They do mean fewer Proguard annotations.)
Bug 1063750 - Part 4: Test navigating to about:home?panel= URLs. r=mcomella

There are no consumers of this (that I can see) in the tree, so we need
to test that it doesn't go away.