Allow VO tables to be read/written directly from astropy.table.Table class
Added comments
Removed docstring that was included by mistake
Follow on to #524.  This adds a number of features to the io.votable core to better support io.table read/write integration.

Adds support for identifying VOTables from their header (is_votable).

Adds support for loading a single table by its ID (and ignoring all other tables).

Adds support for setting the ID of the table being created using `from_table`.

Adds some unit tests.
Merge pull request #20 from mdboom/votable/table-interface

Follow on to #524
Fix tests on Numpy 1.4 and Python 3.x
Merge pull request #21 from mdboom/votable/table-interface

Fix tests on Numpy 1.4 and Python 3.x
Add support for `equivs` kwarg on `convert_units_to`.
equivs -> equivalencies
Implemented e-terms
Fixes to E-term implementation.
Updated comments on e-terms
Fixed id -> table_id
Significantly expanded the Table I/O docs to make them more user-friendly
Added examples of IPAC tables as suggested by @mdboom
Added links to different table format descriptions as suggested by @mdboom
Renamed section
Initial version of stability document
Only check for overwriting if output is a string
Hard-code HTML table for now to customize look