Merge branch dispatcher and broke out pagination callbacks to use it

* Merge branch 'dcornejo-master'
* Broke out pagination callback API from state data callbacks
  * New pagination callback API uses new dispatcher from netgate, thanks @dcornejo
   * Register callback with: `clixon_pagination_cb_register()`
   * Use accessor functions `pagination_offset()`, `pagination_limit()`, etc
 * Reverted state data callback API to pre-5.3 (see C/CLI API changes below)

lib/clixon/clixon.h.in

@@ -108,6 +108,7 @@ extern "C" {
 #include <clixon/clixon_xml_nsctx.h>
 #include <clixon/clixon_xml_vec.h>
 #include <clixon/clixon_client.h>
+#include <clixon/clixon_dispatcher.h>
 
 /*
  * Global variables generated by Makefile