added color output operator
added default constructor
added f32 multiply
added add/sub operators, comments for future todos
moved djb2hash to StringAdditions
removed default constructor since it was buggy anway
First shot at animation system

* moved Variant out of UniformBlock into seperate file again, added
operators
* Animation now works
* Animations can be added to Layers
* Layers can process animations
* AnimationSystem is triggered by ui->update() to process all layer
animations
* added opacity to layer
* Compositor now actually uses opacity for drawing layers
* fixes #19