fix mesh elements buffer wrong size calculation
make size fields in Mesh specify elements and not triangles

- before the size/alloc/used fields would mean whole faces (in most
  cases triangles)
- now these specify elements (indices), so instead of saying that the
  mesh consists of x triangles, these now mean x indices (of which three
  might make up a triangle)
grid test section in Makefile
rought first version of mesh_map/unmap functions
fucking naming things is hard
switch uint32_t with uint64_t
add grid.c/h octree grid datastructure thing
added wire shader files (not working yet)
remove unused NUM_MESHES define
Merge branch 'iso-rpg' of github.com:rakete/cute3d into iso-rpg

Conflicts:
	geometry.c
	render.c