* Fixed: [Error message seen twice in some cases](https://github.com/clicon/clixon/issues/325)
* Extended `-l` command-line option to all clixon commands with a `none` option, eg `-l n` directs logging to `dev/null`
Check of enable-http-data config option
HTTP/2 Return 400 bad request if no path match
Test: updated yang file revisions, extended restconf config with http-data
* `CLICON_RESTCONF_PATH` is now obsolete for sure
* Instead if you use fgci/nginx:
* Use `restconf/fcgi-socket`
* Ensure `<CLICON_FEATURE>clixon-restconf:fcgi</CLICON_FEATURE>` is set
* Added default values to restconf-config and save fcgi-socket-path in memory
* Removed obsolete options:
* `CLICON_YANG_LIST_CHECK`
* `CLICON_RESTCONF_PATH` (moved to restconf/fcgi-path)
* Fixed: Configure option `CLICON_RESTCONF_PRETTY` was marked as obsolete but was still used.
* `CLICON_RESTCONF_PRETTY` is now obsolete for sure
* Instead restconf/pretty is used with API function restconf_pretty_get()
* 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
- Added autoconf config options, temporary for nghttp2 development: `--disable-evhtp`and `--enable-nghttp2`.
- Added special case for api-path:s beginning with //
* clixon_restconf daemon is installed in /usr/local/sbin (as clixon_backend), instead of /www-data
* `configure --with-wwwdir=<dir>` remains but only applies to fcgi socket and log
* New option `CLICON_RESTCONF_INSTALL_DIR` is set to where clixon_restconf is installed, with default `/usr/local/sbin/`
* Restconf drop privileges user is defined by `CLICON_RESTCONF_USER`
* `configure --with-wwwuser=<user>` is removed
* clixon_restconf drop of privileges is defined by `CLICON_RESTCONF_PRIVILEGES` option
* New clixon-restconf@2020-05-20.yang revision
* Added: restconf `log-destination`
This include plugin module init and exit functions
New type: clixon_plugin_t exposed via public API while struct clixon_plugin is private
- Makefile changes for static linkage using "LINKAGE=static"
- Moved nacm external init to later stage in backend_main
* Not backward compatible: All uses of the ca-auth callback in restconf plugins must be changed
* New version is: `int ca_auth(h, req, auth_type, authp, userp)`
* where `auth_type` is the requested authentication-type (none, client-cert or user-defined)
* `authp` is the returned authentication flag
* `userp` is the returned associated authenticated user
* and the return value is three-valued: -1: Error, 0: not handled, 1: OK
* For more info see [clixon-docs/restconf](https://clixon-docs.readthedocs.io/en/latest/restconf.html)
* evhtp restconf closes session on -1 fatal error (no hang)
* restconf auth-type=none call ca_auth callback
* main example for auth_type=none uses basic auth to get user but without passwd check
* Except `CLICON_RESTCONF_DIR` which remains in clixon-config.yang due to bootstrapping
* -d <dir> option removed
* This applies to both evhtp and fcgi RESTCONF
* Both can also read config from backend, and be started from backend
* You may need to move config as follows (from clixon-config.yang to clixon-restconf.yang)
* CLICON_RESTCONF_PRETTY -> restconf/pretty
* CLICON_RESTCONF_PATH -> restconf/fcgi-path
* Not backward compatible: All uses of the ca-auth callback in restconf plugins must be changed
* New version is: `int ca_auth(h, req, auth_type, authp, userp)`
* where `auth_type` is the requested authentication-type (none, client-cert or user-defined)
* `authp` is the returned authentication flag
* `userp` is the returned associated authenticated user
* and the return value is three-valued: -1: Error, 0: ignored, 1: OK
* For more info see [clixon-docs](https://clixon-docs.readthedocs.io/en/latest/restconf.html)
* New clixon-restconf@2020-12-30.yang revision
* NACM recovery user session is now properly enforced. This means that if `CLICON_NACM_CREDENTIALS` is `except` (default), then a specific `CLICON_NACM_RECOVERY_USER` can make any edits and bypass NACM rules.
* If a default value is replaced by an actual value, RESTCONF return values have changed from `204 No Content` to `201 Created`
* clixon-config.yang: Removed default valude of CLICON_NACM_RECOVERY_USER
* Added: stats RPC for clixon XML and memory statistics.
* Added: restart-plugin RPC for restarting individual plugins without restarting backend.
* xml-stats moved from clixon-config.yang as state data to an rpc `datastats` in clixon-lib.yang
* Experimental: restart_plugin
* Two new plugin callbacks added
* ca_daemon: Called just after a server has "daemonized", ie put in background.
* ca_trans_commit_done: Called when all plugin commits have been done.
* Note: If you have used "end" callback and usign transaction data, you should probably use this instead.
* If you have used, `ys`, add `xml_spec_set(x, ys)` after the statement
* If you have `xml_type_set(x, TYPE)` or `xml_prefix_set(x, PREFIX)` immediately after the statement, you can remove those and set them directly as: `xml_new(name, PREFIX, xp, TYPE)`
