* NACM module support (RFC8341 A1+A2)
* Recovery user "_nacm_recovery" added.
* Example use is restconf PUT when NACM edit-config is permitted, then automatic commit and discard are permitted using recovery user.
* Example user changed adm1 to andy to comply with RFC8341 example
* Yang code upgrade (RFC7950)
* RPC method input parameters validated
* see https://github.com/clicon/clixon/issues/4
* Correct XML namespace handling
* XML multiple modules was based on "loose" semantics so that yang modules were found by iterating thorugh namespaces until a match was made. This did not adhere to proper [XML namespace handling](https://www.w3.org/TR/2009/REC-xml-names-20091208), and causes problems with overlapping names and false positives. Below see XML accepted (but wrong), and correct namespace declaration:
```
<rpc><my-own-method></rpc> # Wrong but accepted
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> # Correct
<my-own-method xmlns="http://example.net/me/my-own/1.0">
</rpc>
```
* To keep old loose semantics set config option CLICON_XML_NS_ITERATE (true by default)
* XML to JSON translator support for mapping xmlns attribute to module name prefix.
* Default namespace is still "urn:ietf:params:xml:ns:netconf:base:1.0"
* See https://github.com/clicon/clixon/issues/49
* Changed all make tags --> make TAGS
* Keyvalue datastore removed (it has been disabled since 3.3.3)
* debug rpc added in example application (should be in clixon-config).
* `CLICON_YANG_DIR` is changed from a single directory to a path of directories
* Note CLIXON_DATADIR (=/usr/local/share/clixon) need to be in the list
* CLICON_YANG_MAIN_FILE Provides a filename with a single module filename.
* CLICON_YANG_MAIN_DIR Provides a directory where all yang modules should be loaded.
* Change all @datamodel:tree to @datamodel in all CLI specification files
* If you generate CLI code from the model (CLIXON_CLI_GENMODEL).
* For backward compatibility, define CLICON_CLI_MODEL_TREENAME_PATCH in clixon_custom.h
* Removed return value ymodp from yang parse functions (eg yang_parse()).
* New config option: CLICON_CLI_MODEL_TREENAME defining name of generated syntax tree if CLIXON_CLI_GENMODEL is set.
* Improved unknown handling
* Configure option `CLICON_YANG_DIR` is changed from a single directory to a path of directories
* Note CLIXON_DATADIR (=/usr/local/share/clixon) need to be in the list
* Except clixon-config module due to bug reported below
* Bug: Top-level Yang symbol cannot be called "config" in any imported yang file.
* datastore uses "config" as reserved keyword for storing any XML whoich collides with code for detecting Yang sanit
* Clarified semantics of main yang module:
* -y option to commands MUST specify filename
* CLICON_YANG_MODULE_MAIN MUST specify a module
* yang_parse() changed to take either filename or module name and revision.
* Removed clicon_dbspec_name[_set]().
* Use yang_main_module_name() instead.
* Replaced yang_spec_main with yang_spec_parse_module
* Added yang_spec_parse_file
