* More precise Yang validation and better error messages

* For Example, adding bad-, missing-, or unknown-element error messages, etc instead of operation-failed
* Removed delete-config support for candidate db since it is not supported in RFC6241.
* Switched the order of `error-type` and `error-tag` in all netconf and restconf error messages to comply to RFC order.
* Added example_rpc RPC to example backend
* Renamed xml_namespace[_set]() to xml_prefix[_set]()
* Some restconf error messages contained "rpc-reply" or "rpc-error" which have now been removed.
* Netconf/Restconf RPC extra input arguments are ignored (https://github.com/clicon/clixon/issues/47)

ROADMAP.md

@@ -1,36 +1,34 @@
 # Clixon roadmap
 
-In prio order
-
-High prio
+## High prio
 - NACM (RFC 8341) 
-  - Module rules
+  - Module rules (done)
   - Data node rules (read/create/delete/update/execute)
 - Special handling of the initial startup transaction to avoid exit at startup
   - Possibly - draft-wu-netconf-restconf-factory-restore-03
 - Handle revisions to data model.
   - Possibly draft-wang-netmod-module-revision-management-01
+- XML [Namespace handling](https://github.com/clicon/clixon/issues/49)
 
-Medium prio:
-- Input validation on custom RPCs/ 
+## Medium prio:
+- Input validation on custom RPCs/ (done)
   - [Sanity checks](https://github.com/clicon/clixon/issues/47)
 - Support for XML regex's.
   - Currently Posix extended regular expressions
 - Support a plugin callback that is invoked when copy-config is called.
 - Preserve CLI command history across sessions. The up/down arrows
 
-Low prio:
+## Low prio:
 - Provide a client library to access netconf APIs provided by system services.
+  - Netconf backend (Clixon acts as netconf controller)
 - Support for restconf call-home (RFC 8071)
-- Support for restconf PATCH method
 
 Not prioritized:
-- XML [Namespace handling](https://github.com/clicon/clixon/issues/49)
+- Support for restconf PATCH method
 - NETCONF
   - Support for additional Netconf [edit-config modes](https://github.com/clicon/clixon/issues/53)
   - Netconf [framing](https://github.com/clicon/clixon/issues/50)
   - [Child ordering](https://github.com/clicon/clixon/issues/22)
-- Netconf backend (Clixon acts as netconf controller)
 - Restconf
   - Query parameters
 - Streams (netconf and restconf)
@@ -38,7 +36,7 @@ Not prioritized:
 - Jenkins CI/CD and webhooks
 - YANG
   - RFC 6022 [NETCONF monitoring](https://github.com/clicon/clixon/issues/39)
-  - Deviation, belongs-to, min/max-elements, action, unique
+  - Deviation, min/max-elements, action, unique
 - Containers
   - [Docker improvements](https://github.com/clicon/clixon/issues/44)
   - Kubernetes Helm chart definition