ENH: File is a context manager
ENH: File is a context manager

pyfive.File can be used as a context manager.  For example:

with pyfive.File as f:
    dset = f['dataset']

Files opened by the class are closed at the end of the with block, file-like
object are not closed and should be handled in the context where they were
opened.

jjhelmus/pyfive