in unit testing without display plots, the same figure would be used
over and over again. This is problematic when mixing 3D and 2D axes

If this line
from setuptools import find_packages, setup
is run after
from distutils.extension import Extension

a wrong Extension class is used

Basic support for OpenCL (experimental)

See merge request pycodegen/pystencils!29

Fix get_type_of_expression for constants like sympy.pi

See merge request pycodegen/pystencils!35

Problem some constant expressions are neither Float,Integer,Rational but
don't have arguments.

>>> isinstance(pi, Integer)
False
>>> isinstance(pi, Float)
False
>>> isinstance(pi, Rational)
False
>>> pi.args
()

Implement sp.Sum, sp.Product

See merge request !38

Contest: ignore two more files if waLBerla is not available

See merge request pycodegen/pystencils!40

The line is only need when running pytest form the root directory

Pre-push hook

See merge request !36

Remove main methods from tests (sorry for adding them)

See merge request !37

Conftest: waLBerla, kerncraft

See merge request !39

Sum and Product have a indexing variable which is a Atom but not a free
symbol

... or code will be executed when pytest is collecting the tests.
I found out that I can use "-s" to convince vim-test to show me test
output.

- how could this not have been caught by the tests?!

- str(e) did work in previous pytest version
- but the correct usage is str(e.value)
- in newer pytest version the string for the e object is changed so
  the tests did not work any more

- numpy constants get directly their numpy type
- integer functions check for integer types at construction

- for example: sqrt(cast_func(3, double)) previously printed "sqrt(3)"
  instead of "sqrt(3.0)" leading to errors in CUDA code

Add KernelFunction.fields_written

See merge request !33

We cannot compile with kernel name `kernel` since `kernel==__kernel` is
a keyword in OpenCL