Implement C++ code generation
Implement C++ code generation

  - TODO:
    - CMake build target
    - Copy generated files to correct places
  - Problems with generated code:
    - sample::poisson_square overloads
    - sample::stratified and scale::range produce invalid/duplicate calls

cginternals/glkernel,cginternals/glkernel,cginternals/glkernel,cginternals/glkernel,cginternals/glkernel