Add GPU2 wrapper in matfaust for functions: factors, numfactors, nbytes, disp,...

Add GPU2 wrapper in matfaust for functions: factors, numfactors, nbytes, disp, full, norm, normalize, size.

- new functions copy*() in Faust::MatSparse
- new function FaustSpMat2mxArray in faust2Mx.
- generic (CPU/GPU2) transformFact2*MxArray() functions.
- deleting matfaust Faust get_fact(or)_nonopt (deprecated).
- new function clone in TransformHelperGen.
- new function getData in Transform (CPU).
- new functions get_fact*, get_product (result sent to CPU) in TransformHelper<FPP,GPU2>.