Initial MPI version. Dummy implementation: calls are made to parallelize Scenery::rayTrace, but no raytracing actually occurs.
MPI actually working, at least for quantity "intensity".
MPI: move all the raytrace logic into Scenery::rayTrace
Merge branch 'master' into mpi
MPI: use a buffer instead of a temporary file when cloning remotely
MPI: works as long as gyoto-mpi-worker is in the PATH, which is the case by default.
MPI: support all the quantities except impactcoords
MPI: support using provided impactcoords
Merge branch 'master' into mpi
MPI: Get requested quantities from data pointer instead of Scenery.
MPI: support computing impactcoords
MPI: compile (and run) fine with and without MPI
MPI: install gyoto-mpi-worker in ${soversdir}
Document MPI dependencies in INSTALL