aapt: allow toggling "errors instead of warnings"

* This patch makes the default behaviour same as AOSP,
  treating untranslatable strings in any but the default
  locale as warnings.
* Setting the environment variable AAPT_ERROR_ON_WARNING to
  anything will make those warnings, errors.

Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>
Change-Id: I7da98d277495a7646ad64ba2f7e6a6bf14290f98
Frameworks_base: refactor translations

Not others languages in progress

Change-Id: I996968b7a2a70fd3705a13cb7e38d663c2d8b814
Merge remote-tracking branch 'upstream/cm-10.1' into cm-10.1