* 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
* Note that edits to the candidate database or locks will be lost
* To force the CLI to exit if backend restarts, undef `PROTO_RESTART_RECONNECT`
* This is an effect of the fix of [Broken pipe error seen in client (cli) when backend restarts and CLICON_SOCK is recreated](https://github.com/clicon/clixon/issues/312), the CLI behavior on backend restart is changed.
* Added `eof` parameter to `clicon_rpc()` and `clicon_rpc1()` and error handling modified
* Made NETCONF message handling more strict according to RFC 6241
* Set `CLICON_NETCONF_MESSAGE_ID_OPTIONAL` to true to accept omission of message-id attribute
* Fixed: [need make sure message-id exist in rpc validate #240](https://github.com/clicon/clixon/issues/240)
* Hello message semantics has been made stricter according to RFC 6241 Sec 8.1, for example:
* A client MUST send a <hello> element.
* Each peer MUST send at least the base NETCONF capability, "urn:ietf:params:netconf:base:1.1" (or 1.0 for RFC 4741)
* The netconf client will terminate (close the socket) if the client does not comply
* You can set `CLICON_NETCONF_HELLO_OPTIONAL` to true to use the old behavior of essentially ignoring hellos.
* New clixon-config@2020-03-08.yang revision
* Added: `CLICON_NETCONF_HELLO_OPTIONAL`
* The base capability has been changed to "urn:ietf:params:netconf:base:1.1" following RFC6241.
* 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
* Applies to cli/netconf/restconf/client-api code
* Previous behaviour:
* Close socket after each rpc, but now keeps the socket open until the client terminates
* Kept locks over socket life-cycle, but according to RFC 6241 7.5 a lock should be relaeased when session ends
