Remember and restore last selected change detail (tablet)

Properly remember and restore the last selected change detail
 for each tab. Only affects tablet mode.
Fix: https://twitter.com/HoundDude/statuses/386877279638679552
 (Change 2/2)
Broadcast a status message when a new tab (status) is selected
PatchSetViewer: Support changing changeid without reloading fragment;
 general cleanup
TheApplication: Manage the currently selected status so broadcasts
 are not lost
Changes: Get the status of a changeid

Change-Id: I27e8afbbcb6fa13635cce5a230c1bf165828e7c5