Reflect current state of torch in navigation ring button.

JIRA: CYAN-574

Patch Set 1  -  Initial release
Patch Set 2  -  Show the current state

Change-Id: I82594726df1c0b4b34efdb6e58a0300f99cb1cde
Added support for multiple navigation key bars

System UI was build with the assumption that there is only one
navigation bar at a time, and that this bar is managed by
Phone UI, Tablet UI or TV UI.

This commit adds simple call back facilities at BaseStatusBar
for both, navigation key hints and menu key visibility change
events. These call backs are wired up in Phone UI, Tablet UI
and the TV UI stub.

This allows us to have more than on navigation key bar
in the UI and define those navigation bars directly
in BaseStatusBar, where it is available for all UIs.

Patch Set 2:
* CyanogenMod Code Style
* Added documentation.
* One interface for all
* Added setDisabledFlags() to the list

Change-Id: Id4de440e21c2f5c78b5e185030f9c5e0f7e6bef7
Navring: Fix shortcut for uninstalled app

Fix NPE when the user uninstalls an app that was assigned to a navring
shortcut before.

Change-Id: I3f02fca73cb30e2edbb35d089ad127b35d8233c0
Make system layout fill the window properly on expanded desktop mode.