File resources are assigned resource id's and if an overlay adds one
it renumbers things and breaks compatability. Used to segfault
if you tried before, but now catches it and lets you know what file
caused the problem.
Now old applications will automatically be granted it. Also renamed it from
SDCARD_WRITE to WRITE_SDCARD to be consistent with our other permissions,
and re-arranged how we do targetSdkVersion to actually be usuable for this
kind of stuff.
Note that right now this results in basically all apps being given the
WRITE_SDCARD permission, because their targetSdkVersion is not set. I will
be dealing with that in a future change.
