support tga format texture
tgaTexture: allocate palette buffer using colormap length * size
tgaTexture: scene, collada, and obj loader support tga texture format
add the tga texture loader example
Remove TGATexture class because DataTexture can replace TGATexture class.
Merge branch 'tgaTextureSupport' of https://github.com/DaoshengMu/three.js into dev

Conflicts:
	build/three.min.js