py-sqlparse: update to 0.2.4

Release 0.2.4:

Enhancements
* Add more keywords for MySQL table options (pr328, pr333, by phdru).
* Add more PL/pgSQL keywords (pr357, by Demetrio92).
* Improve parsing of floats (pr330, by atronah).

Bug Fixes
* Fix parsing of MySQL table names starting with digits (issue337).
* Fix detection of identifiers using comparisons (issue327).
* Fix parsing of UNION ALL after WHERE (issue349).
* Fix handling of semicolon in assignments (issue359, issue358).

(adam)