Adds Model.sync()

Driver must implement .sync() or Model.sync() will return an error on
callback.
Adds initial mysql driver sync

Fields are still very static, I need to create options for almost every
property to allow for tweaks (like VARCHAR size, FLOAT/INT size, DATE
instead of DATETIME, ...)
Fixes bug from previous commit having an extra parenthesis
Adds test for Model.sync()

Currently there's only mysql.sync