Added edited lessons on HDF5 after reviewer comments

@jdblischak Here's a clean PR with an edited lesson.  I fixed the typos and comments from the earlier PR.  I've also done a more in depth lesson on creating HDF5 files before diving into the real world data set.  I think I've addressed all of the reviewers comments.  Hopefully this made it in before the BC split.
Need a blank line between *Goals* and the list in order for the list to render properly.