Implement GPU randFaust and add a device argument to pyfaust.rand(dev=cpu|gpu).

src/faust_linear_operator/CPU/faust_TransformHelper.h

src/faust_linear_operator/GPU2/faust_TransformHelper_gpu.h

src/faust_linear_operator/GPU2/faust_TransformHelper_gpu.hpp

src/faust_linear_operator/faust_TransformHelperGen.h

wrapper/python/pyfaust.py

wrapper/python/src/FaustCoreCpp.h

wrapper/python/src/FaustCoreCpp.hpp

wrapper/python/src/FaustCoreCy.pxd

wrapper/python/src/_FaustCorePy.pyx