Change APP_SWITCH key event to open Android 4.0 recent apps switcher

Without this patch it opens the old Gingerbread-style recent apps.

Thanks to XDA forum member evilisto for demonstrating how to make this change:
http://forum.xda-developers.com/showthread.php?t=1450138

Patch Set 2: Fixed commit dependencies
Patch Set 3: Open app switcher when key is released rather than when it is
             first pressed, to conform with the behaviour of other keys.

Change-Id: Iea04c3015b773b5f375a01a9ee30c5130de13dff