Add append_hdf5 to fileformats/__init__.py
Increase test coverage
Replace calls to dot with matrix_multiply (changed name)
Fix signature to include unit
Fix read_hdf5 to create dims indirectly
Fix crash in hfarray.__repr__
Compress result of DataBlock.report, increase flexibility in output.

Gained report_maxwidth, report_units and report_minmax options for
optimization of report output.