We now create the correct user defined default material.
Fixed error message to match XNA.
Throw an error when vertex weights are not found for skinned models.
Added exception when the skeleton is not found for a skinned mesh to match XNA.
Added exception to match XNA for wrong weight format.
Added a test for ModelProcessor.DefaultEffect, but the assert is disabled for now.
Fixed test for vertex weights.
Merge pull request #3068 from SickheadGames/defaultmat

Fixed ModelProcessor.DefaultEffect