Updated CompilerFlags_Fortran.cmake

* Updated CompilerFlags_Fortran.cmake:
  * added -heap-arrays 1024 to the ifort compiler options to put large temporary (dummy)
    arrays on the heap rather than on the stack.  The latter can cause segmentation faults
    when calling a subroutine with large arrays as arguments.
  * -mcmodel=medium -> -mcmodel=large for ifort  +  moved it from CMAKE_Fortran_FLAGS
    to CMAKE_Fortran_FLAGS_ALL
  * build CMAKE_Fortran_FLAGS_RELWITHDEBINFO from the proper blocks
  * print the proper compiler flags used.  Make sure you choose the right line, typically
    release or release with debug info, corresponding to CMakeLists.txt
Added README to / for GitHub
Updated README