Turn off byte-code caching

The version I've been using is really pretty inconvenient.
Update php-mode.el to current master

It should resolve some of the syntax-highlighting problems I've been so
annoyed with.
Add basic embedding of sql-mode in php-mode via mmm-mode

This is not exactly flawless - the only supported SQL string delimiter
is ", and only two variable names are recognized as containing SQL.

Still, it may serve to make day-to-day programming a bit easier.