update slides

slides/images/Blocking.png

slides/images/MPI-datatypes.png

slides/images/SPMD.png

slides/images/buffered-mode.png

slides/images/cluster.png

slides/images/communicator-split.png

slides/images/communicator.png

slides/images/deadlock-prevention.png

slides/images/distributed-memory.png

slides/images/inf-runtime.png

slides/images/non-blocking-detailed.png

slides/images/non-blocking.png

slides/images/p-runtime.png

slides/images/p2p.png

slides/images/runtime.png

slides/images/shared-memory.png

slides/images/standard-mode.png

slides/images/synchronous-mode.png

slides/pages/recap.md