Fixes issue #388
Fixes invalid SQL preventing insertion of dummy post & pages
Fixes migrations 30, 40, 50.
These use $table (query object) in SQL statements.
To cater for this usage using the object as a string will return the table name.
Fixes insert_get_id() of the Query class.
Creates public instance() method to allow other classes to run PDO methods from the connector context
Merge pull request #413 from studioromeo/fix/388

Dev install fixes