txc_dxtn--, LuaJIT--, OZ_NET--, ozCore misc++

- removed dummy txc_dxtn, "force_s3tc_enable=true" does the trick
- removed LuaJIT support, it cannot execute precompiled code
- commented out network code and removed OZ_NET
- updated README
- ozCore
  * mCopy, mMove & co. accept int instead of size_t
  * containers: some fixes of resize(), element destruction (aFill() is not OK)
Input++, Mind++ & fixed,, SDL2 fixes

- matrix
  * Orbis::obj() is templated to enable casting to an Object-derived type
- nirvana
  * Mind works properly again, COLLISION_UPDATE_BIT
- client
  * Input
    + switched from raw input to mouse warping for SDL2 relative mouse input =>
      fixed duplicated mouse move SDL2 bug
    + mouse acceleration removed, SDL2 mouse warping takes care of it
  * fixed SDL2 resolution mess when restoring minimised fullscreen window