Add the "nprocs" option to projector objects and scene's project method.

Signed-off-by: Martin Raspaud <martin.raspaud@smhi.se>
Solve the multiple channel resolution with automatic resampling radius.

Signed-off-by: Martin Raspaud <martin.raspaud@smhi.se>
Merge commit 'b540de87a01e45ae85f76596f7747a4421f68dca' into HEAD