IQM model support

IQM Model support

AARadiant, from the Alien Arena project, had a plugin for IQM Models. This plug-in was imported in NetRadiant.

Unfortunately, this plug-in was not complete: model texture support was missing!

Following IQM specifications, model texturing has been implemented. This is fresh and there may be bugs, tell us if you find some!

Learn more about this on related merge threads: plugin code import, model texturing implementation.