Coverity: fix some out-of-bounds access/read/write issues

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9876 387891d4-d844-0410-90c0-e4c51a9137d3
add Coverity modeling file

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9877 387891d4-d844-0410-90c0-e4c51a9137d3
add .gitignore file :D

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9878 387891d4-d844-0410-90c0-e4c51a9137d3