MySQL enhancements

Hello! 

We're using scala-query with MySQL in a project where we need to set some table properties for tables during generation (e.g. Engine=InnoDB). Currently this seems to be impossible, and therefore we forked and added support for general TableOptions. 

The logic is pretty much the same than the one currently used with ForeignKeys. We created real implementation only for MYSQL-databases, but it should be relatively easy to implement with other databases. 

Please see fork's README-file for usage instructions. 

Best Regards, 

Jussi Vesala