Efficiently receive data and fill an existing buffer

Property definitions

mpi $ MPI :: recv_fill
	# Efficiently receive data and fill an existing buffer
	fun recv_fill(buffer: Receptacle, source: Rank, tag: Tag, comm: Comm)
	do
		buffer.recv_fill(self, source, tag, comm)
	end
lib/mpi/mpi.nit:78,2--82,4