two bug fixes: kOfxParamPropIncrement only exists for Double; kOfxParamPropIncrement and kOfxParamPropDigits have only one dimension, even for Double2D or Double3D
bug fix: bools can not yet be animated, and use the Knobs to set the OFX host animation capabilities
initial OFX CustomParam support (not yet activated)
simplify KnobFactory: 150 lines of codes were zapped in the process! And the code is readable!