add low ram prop

Users can now force this off so this enables them to decide
themselves if they want fancy gfx or likely better performance.

Change-Id: I6d2436058889276687c303bce331c170075b193c
remove min_free_kbytes tweak

Change-Id: If3222f943a3ff17d822d13fabed2b3a62726ac26
Merge branch 'cm-11.0' of https://github.com/Mustaavalkosta/android_device_htc_ace into cd-4.4