Fix mantis 3087 (from Yarn)

Readd translation support for default escort gauge header text

git-svn-id: svn://svn.icculus.org/fs2open@10976 387891d4-d844-0410-90c0-e4c51a9137d3
Fix mantis 3086 (from Yarn)

Add special case to avoid crash from mismatched quotes in
tstrings.tbl German text

git-svn-id: svn://svn.icculus.org/fs2open@10977 387891d4-d844-0410-90c0-e4c51a9137d3
From MageKing17: Fix for Mantis 3085: Unhelpful error reporting in hud_gauges.tbl if an invalid gauge type is specified.

git-svn-id: svn://svn.icculus.org/fs2open@10978 387891d4-d844-0410-90c0-e4c51a9137d3