adds in previously uncaught errors and collects them together by HTTP status code to reduce copy-and-paste coding in previous versions of these files
adding in a couple of additional errors that are thrown from methods invoked from within the model and broker RESTful API classes
Merge pull request #160 from tjmcs/tb/catch-uncaught-api-errors

Fixes #158 (Unhandled Exceptions/Errors in RESTful API)
Changes to support use of the (SMBIOS) UUID as a node identifier
Fixes the `hanlon config ipxe` (or the equivalent RESTful call) so that it
outputs the new `mac_id` field instead of the old `hw_id` field as part
of the `boot` URI
Merge branch 'tb/use-serial-no-as-node-id' of github.com:tjmcs/Hanlon into tb/use-serial-no-as-node-id