Removed vUv0 varying when it's not used;
Multiple maps with equal transform use one varying.
Merge pull request #72 from guycalledfrank/less-varyings

Less varyings
Fixed texture flipping on particles
Merge pull request #16 from playcanvas/master

Merge pull request #72 from guycalledfrank/less-varyings
Merge pull request #73 from guycalledfrank/particle-unflip

Particle unflip
[RELEASE] v0.158.9
[VERSION] v0.159.0-dev
Merge pull request #17 from playcanvas/master

merge