Fix Mantis 3077 (Subtitles including a message will crash multiplayer games). 

git-svn-id: svn://svn.icculus.org/fs2open@11034 387891d4-d844-0410-90c0-e4c51a9137d3
The previously committed version of multi-eval did not include the code to allow it to determine if client side scripts should also be executed on the server. This version does but will break any previously created missions. 

git-svn-id: svn://svn.icculus.org/fs2open@11035 387891d4-d844-0410-90c0-e4c51a9137d3
Opps. Only need that defined once!

git-svn-id: svn://svn.icculus.org/fs2open@11036 387891d4-d844-0410-90c0-e4c51a9137d3