Turn on lint-on-save for all XML types, and move some code

Turn on lint-on-save for all XML editor types since there are per-file
rules for other file types than layouts now (such as manifest files
and drawable files).

Move some methods up from ResourceXmlDetector such that XML detectors
that aren't resource detectors (such as manifest detectors) can access
them. Also move some constants around.

Change-Id: Iba8972142ffd8c8da43249f9d302f69ce7fe7add
7 files changed