Colored shadow added

Colored shadow added
Added ParserOptions.materialFunction.
Fixed the ParserOptions.defaultDependencyFunction.
Remove comments
Fix sprite shader
Merge branch 'dev' of https://github.com/QW0101/minko into QW0101-dev

Conflicts:
	src/aerys/minko/render/shader/part/phong/attenuation/ExponentialShadowMapAttenuationShaderPart.as
	src/aerys/minko/render/shader/part/phong/attenuation/PCFShadowMapAttenuationShaderPart.as
	src/aerys/minko/render/shader/part/phong/attenuation/VarianceShadowMapAttenuationShaderPart.as
Avoid context configuration if the pass is disabled
Merge commit '8f334aa72fae9e6c2afe6e2c2400f96e5d0b534e' into dev

Conflicts:
	src/aerys/minko/render/shader/part/phong/attenuation/PCFShadowMapAttenuationShaderPart.as
Merge branch 'dev' of aerys.in:minko into dev
Merge branch 'origin/material-function'
Remove unused and confusing shadowStrength option (just scale the color if you need it). Fix coding style.