Making the mysql deletion cleaner to touch only those tables that have new records in them

Hey guys, here is a little something to speed up the deletion strategy under mysql.

basically the idea is that it checks the mysql metadata and gets the list of tables that have new records in them and then deletes data only from those tables. It gives really nice boost on large projects where there are dozens of tables to clean up.

I've described the principles in this little blog post, in case you're interested http://theosom.com/p/SFGN