Extended cli_auto_show() with with-defaults argument, also changing its signature
Example: Added with-defaults argument to clispec
C-API: Added with-defaults argument to clicon_rpc_get_config
Replaced with-defaults prefix/namespace with constants
* In the autocli and handcrafted CLI:s using `expand_dbvar()` the CLI expansion followed the leafrefs to the sources, ie the origin of the leafrefs
* Instead leafref expansion now only looks at the leafrefs
* First hello is 1.0 EOM framing, then successing rpc is chunked framing
* See
* [Netconf framing](https://github.com/clicon/clixon/issues/50), and
* [Clixon does not switch to chunked framing after NETCONF 1.1 is negotiated](https://github.com/clicon/clixon/issues/314)
* C:
* Moved netconf framing code from netconf application to clixon lib
* Test:
* New expecteof_netconf and adjusted other expect scripts to handle NETCONF 1.1 framing
* Closer adherence to RFC 7950. Some of this is changed behavior, some is new feature.
* Essentially instead of looking at the referring leaf, context is referred(target) node
* Validation uses referred node
* Validation changed to use type of referred node, instead of just "string"
* Auto-cli
* Changed to use type of referred node for typecheck
* Completion uses referred node
* Required instance / less strict validation
* New: Leafrefs must refer to existing data leaf ONLY IF YANG `required-instance` is true
* Previous: All leafrefs must refer to existing data leaf node
* Fixed: [Autocli does not offer completions for leafref to identityref #254](https://github.com/clicon/clixon/issues/254)
