Suppress support and location tracking for translation detector

This changeset adds support for suppressing lint errors on
translations. For a missing translation, place the suppress attribute
on the default language key. For strings defined in other languages
but not the default locale, place the attribute on the extra
translation.

This required adding better location tracking (which is also
beneficial in that the translation warnings will show up as editor
underlines in Eclipse etc). Instead of having errors generated for
each locale ("the following strings are missing from locale X") it now
generates a unique error for each string, listing which locales it's
missing from. This also solves a different issue where the list of
missing strings was truncated when large; there's no more truncation
now.

Change-Id: If63e92a6a750a5314af2f11441347cf9fc0b0a15
6 files changed