Add returns section to to_json numpydoc string
Add checks in __eq__ to descriptive_equality

descriptive_equality should not say that the tables look the same when __eq__
evaluates to False
Use appropriate tests to check for array equality

Fixes #435
Reset file position before trying to parse

Fixes #434
Add better tests for parse_biom_table

Previously, this function was not tested, which led to the surprise
identification of #434
Merge pull request #436 from adamrp/issues_434_435_and_some_other_stuff

Issues 434 435 and some other stuff