Create README.md

The purpose of this fork is to improve (in my opinion) how the effects are handled compared to JessyInk. In this fork, the order of an effect is defined regarding the position of its layer regarding the sibling. The effect is not is the object anymore but in a clone of the object. Thus, we are able to define many effects for one object.

Features added:
  - matrix transform effect: just move the clone created with this effect, and the transformation matrix will be applied to the original (skew is not handled yet, I do not know the right formula)
  - SMIL animate effect: you can change a parameter of an object