New API is as follows:
* `clixon_xml2file()` - Print internal tree as XML to file
* `clixon_xml2cbuf()` - Print internal tree as XML to buffer
* `clixon_json2file()` - Print internal tree as JSON to file
* `clixon_json2cbuf()` - Print internal tree as JSON to buffer
* `clixon_cli2file()` - Print internal tree as CLI format to file
* `clixon_txt2file()` - Print internal tree as text format to file
* Added `skiptop` parameter, if set only apply to children of a node, skip top node
* default is 0
* Functions are merged, ie removed and replaced with more generic functions
* `xml2json_cbuf()`: Added `skiptop` parameter: `xml2json_cbuf(..., int skiptop)`
* `xml2json()` and `xml2json_cb()` merged into `xml2json_file()` with `skiptop`
* Replace `xml2json(...)` with `xml2json_file(..., stdout, 0)`
* Replace `xml2json_cb(...)` with `xml2json_file(..., 0)`
* `clicon_xml2cbuf()`: Added `skiptop` parameter: `clicon_xml2cbuf(..., int skiptop)`
* `xml2cli()`: Added `skiptop` parameter: `xml2cli(..., int skiptop)`
* Load/save JSON config file did not work
* Added rfc7951 parameter to `clixon_json_parse_string()` and `clixon_json_parse_file()`
* If set, honor RFC 7951: JSON Encoding of Data Modeled with YANG, eg it requires module name prefixes
* If not set, parse as regular JSON
* Test: added test_db.sh for datastore format tests
NETCONF hello errors, such as wrong session-id, prefix, namespace terminates session
* Instead of returning an rpc-error reply
Changed YANG PATCH enabling:
* Now: `./configure --enable-yang-patch`
* Before: set YANG_PATCH constant in `include/clixon_custom.h`
Refactored Makefile for static linking
* 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
