* Replaces the hardcoded "config" keyword.
* Implemented by a compile-time option called `DATASTORE_TOP_SYMBOL` option in clixon_custom.h
* Tests: added endtest to all tests. Removed all premature exits if BE=0
* Enforcing RFC 7950 Sec 7.6.1 means unassigned top-level leafs (or leafs under non-presence containers) are assigned default values.
* NACM default behaviour is read-only (empty configs are dead-lockedd)
* This applies if NACM is loaded and `CLICON_NACM_MODE` is `internal`
* Fixed: [default values don't show up in datastores #111](https://github.com/clicon/clixon/issues/111)
* Changed commit lock error tag from "lock denied" to "in-use".
* Changed unlock error message from "lock is already held" to #lock not active" or "lock held by other session".
* Fixed [lock candidate succeeded even though it is modified #110](https://github.com/clicon/clixon/issues/110)
* 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)`
w-level general upgrades and as a complement to module-specific upgrade.
* Called on startup after initial XML parsing, but before module-specific upgrades
* Enabled by definign the `.ca_datastore_upgrade`
* [General-purpose upgrade documentation](https://clixon-docs.readthedocs.io/en/latest/backend.html#ge
neral-purpose)
* JSON parse error messages change from ` on line x: syntax error,..` to `json_parse: line x: syntax err
or`
* Unknown-element error message is more descriptive, eg from `namespace is: urn:example:clixon` to: `Fai
led to find YANG spec of XML node: x with parent: xp in namespace urn:example:clixon`.
* C-API parse and validation API more capable
* `xml_spec_populate` family of functions extended with three-value return values
* -1: error, 0: parse OK, 1: parse and YANG binding OK.
* `xml_parse` and `json_parse` API changes
* Three value returns: -1: error, 0: parse OK, 1: parse and YANG binding OK.
* Extended `xml_parse_file2` and `xml_parse_string2` extended API functions with all options available.
* New concept called `yang_bind` that defines how XML symbols are bound to YANG after parsing
* Existing API same except `xml_parse_file` `endtag` argument moved to `xml_parse_file2`
* C-API: Added instrumentation: `xml_size` and `xml_stats_get`.
* Fixed: Enabling modstate (CLICON_XMLDB_MODSTATE), changing a revision on a yang, and restarting made the backend daemon exit at start (thanks Matt)
* Also: ensure to load `ietf-yang-library.yang ` if CLICON_XMLDB_MODSTATE is set
* Renamed startup_db_reset -> xmldb_db_reset (its a general function)
* In startup_extraxml(), check if reset callbacks or extraxml file actually makes and changes to the tmp db.
