register c code for Shape op with GpuArrayVariable and doc the register fct().
better error message.
Disable some GpuCAReduce test cases that aren't implemented.
Test with clinker too as now the Shape Op have c code
skip test error due to notimplemented cases.
Last back of compilation fix to GpuCAReduce
Add GpuCAReduce more cases and remove warning about shape of 0 in infer shape.