- Added test for linear equation system and moved it to pystencils.utils

- added isotropic version

- new functions to easily extract stencil coefficients and visualize them
- Moved stencil functions from lbmpy to pystencils

- constants are typed - no need any more for this parameter

- hash function was not correctly implemented
- sometimes this caused a bug where latex version was not correctly displayed

-> test_numerical_1D notebook

- defined ordering of headers
- lbm split kernels produced different ordering of assignments due to
  usage of a set

- fix for field collection and reduction operations
- support for aligned fields in parallel data handling

- new time loop caches all kernel functions with their argument dict
  -> inner loop just calls C functions with cached kwargs

- not generic enough - does not work if there a multiple blocks

- better latex display for indirect accesses
- new field type 'custom': only custom fields can be accessed indirectly
  no static bounds check possible for custom fields

- option to allocate more memory at end of line and do not generate a
  tail loop, if loop range is not divisible by SIMD width

- different approach in pystencils: absolute indexing

- extended pystencils
- Visualization for list LBM
- not yet working