Simpler implementation of LIGO_LW interface
This PR simplifies the LIGO_LW interface, mainly by deprecating the table-dependent format registrations, in favour of a single format ligolw
where I/O routines now accept (expect?) a tablename=
keyword argument.
In the most common form, the following example:
EventTable.read('events.xml', format='ligolw.sngl_burst')
should be updated to
EventTable.read('events.xml', format='ligolw', tablename='sngl_burst')
This change allows for a simpler implementation of the interface, and also native discovery of LIGO_LW
-format files by their content, not by the file name.
The documentation has been updated to match the new syntax.