This version breaks previous before / after commmit functions in ModelResource. By requiring a status flag as output from the functions it opens resources to be more easily used beyond simply REST functions.
Added
* Added a create_resource function that can create resources constrained to a limited HTTP method. Coupled with the refactored functions that can run after posting, a resource can be used for RPC-like features for when the REST is not a good fit.
Changed
* Removed a redundant line in `DBBase._include_dbbase`.
* Refactored before/after commit functions in ModelResource. Just as the `process_{method}_input` functions return a status with the payload, these functions now return a status as well as a payload. Prior to this change, the assumption of the process was that there may be changes to a database item, or a database item would be replaced with another, but once an adjustment takes place it all goes to an inevitable conclusion of returning SOME item and a status codde. By adding this, a greater range of functionality with the ModelResource is available, including returning simply a message and a status code. In such a case, a ModelResource could use the serialization / validation services, but essentially act as an RPC if need be.