* Merge branch 'dcornejo-master'
* Broke out pagination callback API from state data callbacks
* New pagination callback API uses new dispatcher from netgate, thanks @dcornejo
* Register callback with: `clixon_pagination_cb_register()`
* Use accessor functions `pagination_offset()`, `pagination_limit()`, etc
* Reverted state data callback API to pre-5.3 (see C/CLI API changes below)
- Changed logic on how to find clixon_restconf in pseudo plugin
- Removed ==== in constants to avoid conflict with git merge
- Remove assert
- Added fuzzing for netconf
* You need to change all statedata plugin callback for the new pagination feature
* If you dont use pagination you can ignore the values of the new parameters
* See [User manual pagination](https://clixon-docs.readthedocs.io/en/latest/misc.html#pagination)
* The updated callback signature is as follows:
```
int statedata(clicon_handle h,
cvec *nsc,
char *xpath,
pagination_mode_t pagmode, // NEW
uint32_t offset, // NEW
uint32_t limit, // NEW
uint32_t *remaining, // NEW
cxobj *xstate)
```
* The new callback contains parameters for paging
* Goal is to replace ca_statedata callback
* New plugin callback when lock/unlock occurs
* Add `ca_lockdb` tro plugin init to use it.
* Fixed: Typing 'q' in CLI more paging did not properly quit output
* Output continued but was not shown, for a very large file this could cause considerable delay
* Fixed: Lock was broken in first get get access
* if the first netconf operation to a backend was lock;get;unlock, the lock was broken in the first get access.
* Fixed: [Performance issue when parsing large JSON param](https://github.com/clicon/clixon/issues/266)
* Moved strlen() from for end condition
* Fixed debugging of xpath parser
* Closer adherence to RFC 7950. Some of this is changed behavior, some is new feature.
* Essentially instead of looking at the referring leaf, context is referred(target) node
* Validation uses referred node
* Validation changed to use type of referred node, instead of just "string"
* Auto-cli
* Changed to use type of referred node for typecheck
* Completion uses referred node
* Required instance / less strict validation
* New: Leafrefs must refer to existing data leaf ONLY IF YANG `required-instance` is true
* Previous: All leafrefs must refer to existing data leaf node
* Fixed: [Autocli does not offer completions for leafref to identityref #254](https://github.com/clicon/clixon/issues/254)
* Made NETCONF message handling more strict according to RFC 6241
* Set `CLICON_NETCONF_MESSAGE_ID_OPTIONAL` to true to accept omission of message-id attribute
* Fixed: [need make sure message-id exist in rpc validate #240](https://github.com/clicon/clixon/issues/240)
