Add the ability to read arbitrary hyper-rectangles of dense arrays

[wavefunction91]

For large arrays, it is often impossible to "read in replicated" or "read in on root and scatter" due to memory constraints. Therefore, it is highly desirable to read our data directly into distributed data structures (e.g. block-cyclic, etc). This can be done without parallel IO (although it's drastically improved by it) given the ability to read arbitrary blocks (hyper-rectangles) of data from the calling program.