[2/3] Install persistence support

Add persist.sh to save and restore data across installs.  Initial data
includes property ro.sf.lcd_density and file etc/hosts.  Behavior is
controlled via configuration file etc/persist.conf.

Change-Id: I946d620e06a8dc63a6abec862a7517f8b458f2d1

Conflicts:
	configs/common.mk
Add changelog_gen and getdate

Credit to KAsp3rd for the changelog script and AOKP for getdate script
Add m7 to lunch
Update vendorsetup.sh
removed the remove changelog file at the end as this was causing issues with jenkins.. Rather than appending the log info on first create with >> we create the changelog file with the initial data with > therefore deleting anything that was in the file from the last build
Revert "[2/3] Install persistence support"

This reverts commit 2fafa696fda1e9dde44e644d133209788582aa53.
Merge branch 'jb2' of github.com:CarbonDev/android_vendor_carbon into jb2