Fixed a bug reported by Axem: The scripting API used the wrong functions to determine if a hud gauge is a custom hud gauge.

git-svn-id: svn://svn.icculus.org/fs2open@11102 387891d4-d844-0410-90c0-e4c51a9137d3
don't enable nav system always... that's not how this is supposed to work

git-svn-id: svn://svn.icculus.org/fs2open@11103 387891d4-d844-0410-90c0-e4c51a9137d3
well ok, revert that

git-svn-id: svn://svn.icculus.org/fs2open@11104 387891d4-d844-0410-90c0-e4c51a9137d3
Reverted r10944 and r10945 for now, with the exception of the GL_TRIANGLE_STRIP->GL_QUADS fix.

git-svn-id: svn://svn.icculus.org/fs2open@11105 387891d4-d844-0410-90c0-e4c51a9137d3