For sympy, oo s a number. So pystencils prints a type infinity a double
INFINITY as INFINITY.0

This removed some checks like `ctr1 <= 0` from my kernels

For the calculation of the number of ghostlayers only relative accesses
should be considered like on the CPU version

Pystencils will print two const when printing an assignment to a const numpy.dtype.
With the new type interference, this case can now occur more often

type)

There is now a superior implementation in pystencils_autodiff.

This is actually a AST Node for wrapper code. pystencils_autodiff has
now a AST printer for framework integration code. So framework AST nodes
are now there and kernel AST nodes remain here.