Document that we need to flatten sparsely packed numpy arrays
Document that we need to flatten sparsely packed numpy arrays

The documentation indicated that the translation to Chapel was simple, however
in some cases the arrays need to be flattened before they can be sent to a
Chapel program.  Note that possibility before users run into it.

chapel-lang/pychapel,chapel-lang/pychapel,russel/pychapel,chapel-lang/pychapel,russel/pychapel,russel/pychapel