isisd: API: basic circuit config

Create isis_vty.c and start moving off CLI functions into that.  These
then call newly-added "nice" API wrappers.

Patch contains significant work authored by Christian Franke.

[v2: removed stuff that crept in from the next patch]

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/isisd/isisd.h b/isisd/isisd.h
index d2efaca..2803a64 100644
--- a/isisd/isisd.h
+++ b/isisd/isisd.h
@@ -25,7 +25,11 @@
 
 #define ISISD_VERSION "0.0.7"
 
+#include "isisd/isis_constants.h"
+#include "isisd/isis_common.h"
 #include "isisd/isis_redist.h"
+#include "isis_flags.h"
+#include "dict.h"
 
 /* uncomment if you are a developer in bug hunt */
 /* #define EXTREME_DEBUG  */
@@ -137,6 +141,8 @@
 int isis_area_get (struct vty *vty, const char *area_tag);
 void print_debug(struct vty *, int, int);
 
+void isis_vty_init (void);
+
 /* Master of threads. */
 extern struct thread_master *master;