Binary assets

See #32.

This change moves all binary assets out of git and into the Subversion asset repository at http://91.250.119.121/scm/svn/thrive_assets. Since the `res` directory is pretty empty after that, the `scripts` and `ogre_cfg` directories have been moved up into the root directory.

78c572b also addresses one part of #75 by adding a `testing` resource directory that overrides all other resources.