Oops, forgot a return in TextureCachedField.reproducible_hash

See merge request !81

TextureCachedField was using `hash(...)` to disambiguate its instances.
However, `hash` is randomized and will hinder reproducible code
generation

Use reproducible hashlib for representing TextureCachedField

See merge request pycodegen/pystencils!80

Add sympy to known_third_party in .isort.cfg

See merge request pycodegen/pystencils!79

I have installed the newest master of SymPy as editable package.
So `isort` thinks it's one of our libraries.
With this config SymPy is declared as a third party dependency.

Support complex numbers

See merge request pycodegen/pystencils!72

Bugfix: textures should be implemented as textures without changes

See merge request pycodegen/pystencils!73

Add __str__ representation for TextureDeclaration

See merge request pycodegen/pystencils!74

Add option to omit globals when printing C code

See merge request pycodegen/pystencils!75

Run opencl without pycuda

Closes #15

See merge request pycodegen/pystencils!77

correctly print RNG nodes

See merge request pycodegen/pystencils!78

- bugfix: loop counter of vectorized loop now correctly stored as SIMD vector with entries i, i+1, i+2, ...
- basis for in-kernel boundary handling

Fix printing of sp.Infinity/sp.NegativeInfinity

See merge request pycodegen/pystencils!71

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

Fix error in README.md: pystencils[pyopencl] -> pystencils[opencl]

See merge request pycodegen/pystencils!70

Small fixes

See merge request pycodegen/pystencils!69

Declare LoopCounterSymbols nonnegative

See merge request pycodegen/pystencils!68