fixed errors in spec patterns under spec-migration-scripts; Added the defautl driver and MigrationStorageController to the list of exports in index for use in code that wants to build off and extend from these classes
Refactored environmnet options to be provided via the options objects to the run function rather than being used as setters
Renamed the run function in index.js to remove reference to mongo as this library is being abstracted for use with the db of choice