Allow shield augmentation controls to be re-mapped for model point shields.

git-svn-id: svn://svn.icculus.org/fs2open/branches/zookeeper@9933 387891d4-d844-0410-90c0-e4c51a9137d3
Fixed model point shields not getting updated when changing ship class, and removed the warning about generated shield icons.

git-svn-id: svn://svn.icculus.org/fs2open/branches/zookeeper@9934 387891d4-d844-0410-90c0-e4c51a9137d3