libnm-core, all: merge IPv4 and IPv6 address/route types

Merge NMIP4Address and NMIP6Address into NMIPAddress, and NMIP4Route
and NMIP6Route into NMIPRoute. The new types represent IP addresses as
strings, rather than in binary, and so are address-family agnostic.

libnm/NetworkManager.h

@@ -63,6 +63,7 @@
 #include <nm-setting-generic.h>
 #include <nm-setting-gsm.h>
 #include <nm-setting-infiniband.h>
+#include <nm-setting-ip-config.h>
 #include <nm-setting-ip4-config.h>
 #include <nm-setting-ip6-config.h>
 #include <nm-setting-olpc-mesh.h>