Branch/collada transparency fix

[BrettASwift]

Re-apply old transparency mode fixes to Collada loader. The fixes were submitted to ThreeJS here, but were ignored (due to some confusion or lack of understanding). All of the Collada models were being set to transparent by the loader causing them all to be sorted as transparent objects which is why we were getting the clipping on the particles and tracks in mars-game. We should probably continue to look for a Collada alternative as support for it in ThreeJS isn't great and we will keep having to apply these fixes if we update to the latest ThreeJS. @scottnc27603 It might be useful to apply these fixes to the core as well and have them saved for later.

Fixes in this branch:

• Properly set the transparent value in the Collada loader
• Fixes specular, ambient, and other properties being set on transparent objects
• Allows a specular map to be defined by the specularLevel node that 3DSMax uses

Hopefully this is the last time I have to fix this. @kadst43 @nmarshak1337 @AmbientOSX

[kadst43]

:+1:

[eric79]

Has this been applied to the vwf fork of three.js? If not, that is probably why we lost them on the upgrade to the latest three.js.

[BrettASwift]

The one that is submitted to threejs is a vwf/threejs branch.