* Removed validation logic from Resource class, Qt does this internally and is more
standards compliant. This should result in more accurate caching and faster resource
fetching when cache is stale and validation fails.
* Added loaded and failed slots to Resource class, so it does not have to be polled.
* NetworkGeometry now uses multiple Resource objects to download
the fst/mapping file and the fbx/obj models.
* NetworkGeometry is no longer a subclass of Resource
* NetworkGeometry now has signals for success and failure, you no longer
have to poll it to determine when loading is complete (except for textures *sigh*)
Some functionality was removed
* NetworkGeometry no longer has a fallback
* NetworkGeometry no longer loads LODs or has lod logic.
* The number of FBXGeometry copies is greatly reduced.
* Model::setURL no supports fallback URL, delayLoad or retainCurrent option.
This can result in a pop when switching avatars, and there's no longer a default
if avatar loading fails.
