ENH simplify by removing conditional repack
WIP don't keep h5py.File open between method calls
WIP don't leave h5py open between method calls

TODO:

lara object needs to read from archive. But when
you index into lara archive has already been closed.

lara would need to keep track of filename of archive.
WIP fix io.__repr__
WIP all io unit tests pass
DOC update docstrings
TST better unit test coverage of IO class
STY remove trailing whitespace
REF remove la.IO.merge method
DOC tweak
Merge branch 'io'