xt branch tweaks

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@11120 387891d4-d844-0410-90c0-e4c51a9137d3
xt branch: additional optimizations using RAND_MAX_1f

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@11121 387891d4-d844-0410-90c0-e4c51a9137d3
probably good to change the comment too

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@11122 387891d4-d844-0410-90c0-e4c51a9137d3
xt: sprintf length safety

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@11123 387891d4-d844-0410-90c0-e4c51a9137d3