encore: Remove powerHAL for now
OC is much more reliable without it
Cleaned up encore.mk and added 2012 Copyright

1. Removed un-needed overlay.omap3 line from encore.mk
2. Changed the 2011 Copyright to 2012
Sync proprietary-files.txt and setup-makefiles.sh with canonical /vendor
Add watchdogd for petting a watchdog timer

Code shamelessly borrowed from AOSP 4.2.1's
system/core/init/watchdogd.c.