Move OBPQueryParams out of OBPEnvelope
Refactor v1.2.1 api to allow for future version 1.3.0 to share implementations for those calls that have not changed
Add missing file
Fix missing private alias calls
Move error and success case classes into OBPRestHelper
Remove old import of error and success case classes
Move apiPrefix method into OBPRestHelper (which is now a trait instead of a class)
Change vPlusVersion and apiPrefix from vals to defs as they were getting defined before a val they depend on