mpi/miscellaneous examples added

...mpi/miscellaneous/Broadcast_Gather_Scatter/Broadcast_1.cc

...mpi/miscellaneous/Broadcast_Gather_Scatter/Broadcast_2.cc

...i/miscellaneous/Broadcast_Gather_Scatter/Gather_Scatter.c

...ellaneous/Broadcast_Gather_Scatter/Heat_Equation_Gather.c

...dcast_Gather_Scatter/lecture_Broadcast_Gather_Scatter.pdf

jacobi/mpi/miscellaneous/MPI_Datatypes/Subarray.c

...mpi/miscellaneous/MPI_Datatypes/lecture_MPI_Datatypes.pdf

jacobi/mpi/miscellaneous/MPI_Datatypes/tools.c

jacobi/mpi/miscellaneous/Parallel_IO/lecture_Parallel_IO.pdf

jacobi/mpi/miscellaneous/Parallel_IO/write_arr1D.c

jacobi/mpi/miscellaneous/Parallel_IO/write_arr2D.c

jacobi/mpi/miscellaneous/cartesian

jacobi/mpi/miscellaneous/cartesian.cpp

jacobi/mpi/miscellaneous/color_ring.c

jacobi/mpi/miscellaneous/lecture_color_ring.pdf

jacobi/mpi/miscellaneous/subarray