* 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
* 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`
