Small fixes

See merge request pycodegen/pystencils!69

Declare LoopCounterSymbols nonnegative

See merge request pycodegen/pystencils!68

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

Set assumptions for TypedSymbol/cast_func/IntegerFunctionTwoArgsMixIn the SymPy way

See merge request pycodegen/pystencils!66

Bugfix: this bracket should not be here (collate_types returns single type)

See merge request pycodegen/pystencils!63

Bugfix: Align calculation of number of ghost layers on GPU with CPU version

See merge request pycodegen/pystencils!65

Bugfix fields accessed for interpolator access

See merge request pycodegen/pystencils!62

Bugfix avoid east and west const

See merge request pycodegen/pystencils!64

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)

Kernel wrapper

See merge request pycodegen/pystencils!61

Eliminate usages of old name 'equation collection' for `AssignmentCollection`

See merge request pycodegen/pystencils!60

Document backends.json

See merge request pycodegen/pystencils!59

Add AssignmentCollection.{free_fields,bound_fields}

See merge request pycodegen/pystencils!57

Interpolation 24.0.9

See merge request pycodegen/pystencils!56

Remove DestructuringBindingsForFieldClass

See merge request pycodegen/pystencils!55

Extra asserts sympy issue

See merge request pycodegen/pystencils!58