Fix a problem where we would not respect the device's
override display density/size if those had been reset at
some point (to an empty string).
Tweak the tuning of low RAM devices to consider 480x800 as
the base line resolution. That is our target these days.
Improve output of oom and meminfo to include this tuning
information.
Change-Id: Ic9a85b0391b075178c4ac17e64086ef21889f430
635a6d5a0b