add mechanism to always do bind for drivers that need it
  * added flags 'must_preparse', 'must_bind', and 'multiple_bind' to driver info
  * erbi_driver checks these flags at execute time, if must_bind is true, it makes sure
    bind is called (with a possibly empty param list)
  * similar behaviour with must_preparse.. parse is called
  * drivers can still 'decline' these operations, though why?
  * got existing unit tests working; add one test for do.. more needed
  * add support for simulating drivers with and without 'do' to dummy driver
  * add 'info' member to #erbdrv record.. drivers can place new info record here
    used by neo4j to indicate transaction support depending on endpoint
    will add support in dummy driver to toggle various info flags, for testing above changes