* Re-added firebird as a database
* Replaced all callback interfaces with promises
* Changed connection setup to just use a config object - the appropriate adapter object is created by the library.
* Removed mysql adapter, as mysql2 is very similar and does proper prepared statements
* Removed firebird entirely
* Created a standard result object
* Added public `query` method for making arbitrary sql calls
* Added back tests for `node-firebird` adapter. Using this adapter with promises is not currently supported.
* Added support for promises on query execution methods