- abstraction layer for selecting CUDA block and grid sizes
  - line based (was implemented before)
  - block based (new, more flexible)
-  new conditional (if/else) ast node, which is necessary for indexing schemes (guarding if)

- bugfix for CUDA kernels with variable field sizes
- extended tests for pystencils gpu kernels

- windows support
- automatic caching and creation of shared library with all generated kernels
- restrict keyword and function prefixes are preprocessor macros now -> easier to generate one code for linux, cuda, windows

problem in moveConstantBeforeLoops transformation:

--> a should end up here
{
for() {
  const int a = 5;
}
for() {
  const int a = 5
}
}

the "a" of the lower loop was not moved up, since it could not move across first loop (which is wrong)

- added sphinx files for documentation generation
- collected kernel creation functions in new "cpu" and "cudagpu" modules