Add Model#getManagedDisposables() and check if a Disposable already exists before adding.
Set shader before sorting, change signature so its possible to add multiple RenderableProviders at once, add addding with only shader, add adding arrays.
Update gdxinvaders to render the arraylist at once.
Remove ModelInstance#copyMaterials and do that in copyNodes instead, add constructor to specify the id(s) of the node to copy.
Add BaseShaderProvider.
Add some additional methods to ModelBuilder and update the tests with the modified ModelBatch#render signature.
Revert render signature
Fix docs
Merge pull request #328 from xoppa/new3dapi

New3dapi, various changes