Added documentation in comments in test scripts, added example site.sh,
moved evaluation of site.sh later in lib.sh to allow site.sh to override
more lib.sh variables.
* The existing autocli does not support modes, complete paths must be given, eg: `set a b c d 42`.
* In the new auto-cli, automatic modes are present at each YANG syntax node level, eg the above can be given as: `edit a b c; set d 4; top`
* The existing CLI API remains, the new API is as follows: `cli_auto_edit()`, `cli_auto_up()`, `cli_auto_top()`, `cli_auto_show()`, `cli_auto_set()`, `cli_auto_merge()`, `cli_auto_create()`, `cli_auto_del()`.
* See `test/test_cli_auto.sh` for an example of the new API, and `apps/cli/cli_auto.c` for the source code of the new callback API.
* Documentation will be appear and full integration with the main example.
* Added inline state field to clixon-example.yang
* Added new clicon_data_cvec_*() API for generic cvec structs
* A new configuration option `CLICON_CONFIGDIR` has been added for loading of extra config files
* If not given, only the main configfile is loaded.
* If given, and if the directory exists, the files in this directory will be loaded alphabetically AFTER the main config file in the following way:
* leaf values are overwritten
* leaf-list values are appended
* You can override file setting with `-E <dir>` command-line option.
* New clixon-config@2020-10-01.yang revision
* Added option for configuration directory: `CLICON_CONFIGDIR`
* `count`, `name`, `contains`, `not`, as defined in [xpath 1.0](https://www.w3.org/TR/xpath-10)
* `deref`, `derived-from` and `derived-from-or-self` from RFC7950 Section 10.
* in particular in augment/when statements
* Improved error handling
* Verification of XPath functions is done at startup when yang modules are loaded, not when XPaths are evaluated.
* Separation of "not found" and "not implemented" XPath functions
* Both give a fatal error (backend does not start).
