Fixed a warning about a comparison between different enums - EUnifiedMappingType was being compared with EMappingType. In general the FBX SDK is moving away from Get & Set functions to giving direct access to properties, so I have changed GetMappingType() to CurrentMappingType.Get()
A problem with transparency has also been fixed: objects were transparent wrt themselves but were opaque wrt to other objects.
Finally I added the support for "mixing factors" of diffuse, reflective and opacity textures/values.
From Michael Platings: added "LightmapTextures" plugin option that changes the way textures are interpreted so Alessandro's models appear correctly. Also refactored to put many functions in one class to avoid passing around too many arguments to functions.
