Added new aws_db_parameter_group resource for creating RDS DB Parameter Groups.
Added plumbing to allow an optional DBParameterGroupName to be passed when creating an RDS DB instance.
Added missing update support for new aws_db_parameter_group resource
Fixed incorrect ForcesNew settings for parameters and added better acceptance tests to ensure updates are working as expected
Fixed bug with final_snapshot_identifier and skip_final_snapshot and removed apply_method as an option for now and am only supporting immediate mode
Upped the RDS instance creation/destroy timeout to 20 minutes as it regularly takes 12+ minutes to create
Merge pull request #545 from rcostanzo/f-parameter-group

Added new parameter_group_name parameter for creating an RDS DB instance