Hans Goudey
a0e1080428
The main goal here is to remove the need for a C API to the code in `mesh_boolean_convert.cc`. This is achieved by moving `MOD_boolean.c` to C++ and making the necessary changes for it to compile. On top of that there are some other slight simplifications possible to the direct mesh boolean code: it doesn't need to copy the material remaps, and the modifier code can use some other C++ types directly.