Fix Mantis 2885 - SEXP flag to enable/disable primitive sensors, from FUBAR.

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10906 387891d4-d844-0410-90c0-e4c51a9137d3
Fix Mantis 2886 - Option to render External weapon models, besides Tech models, in Weapon lab, from FUBAR.

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@10907 387891d4-d844-0410-90c0-e4c51a9137d3