[OpenCOLLADA] update Externals\cg

- updating cg1.5 to cg3.1
[OpenCOLLADA] Maya: fixing copy textures

- fixing copy textures
- sync max plugin version
Merge pull request #177 from GerhardMaier/OpenCollada-Maya-fixing-copytextures

[OpenCOLLADA] Maya fixing copy textures