factorize the paramCopy code

- use only one entry point instead of two => less copy/paste
- reformat ugly code around the modified regions
- update openfx
*::clone(..., range): remove the range=[0,0] case

- the range=[0,0]  case, is obviously a bug in the spec (range=NULL
copies the whole range)
- avoid double negations: if(copyRange) instead of if(!copyAll)
Merge branch 'workshop' of https://github.com/MrKepzie/Natron into workshop

Conflicts:
	Engine/OfxParamInstance.cpp
	Engine/OfxParamInstance.h