Null key.  This can happen for constants with type 'generic'.

give a warning if we use a numpy version that have a memory leak and that we exeecute code that will hit that leak.

Some c_code regerated by the conv op was hard coding some shape info in some case. When those case are not true, their was no error generated.

fix conv op compilation when the c_code fct was changing the signature of the c code. That is not allowed.

Added ImagesFromNeighbourhoods and two basic tests... but the tests are commented out for the moment