Repair pnghtml compilation
Apply optimization to LayerManager

This makes updateActiveLayersList not do anything if it is not needed.
Make relativeFrame available to layers on update

This makes layers able to drive effects based on how long it as been
active, and not only where in the demo it is globally.
Fix jump to frame update bug
Make start and end methods on layers optional
Repair EffectComposer bug
Add more, clamp existing interpolations
Remove redundant position attribute in layers.json
Remove unwanted logging
Make layers.json be more specific about config

Config variables that are meant for the layer itself should now be but
in config, as it makes the semantics more clear.
Merge pull request #15 from ninjadev/nyn

Lots of individual fixes