split 'libosmocore' from openbsc codebase

This library is intended to collect all generic/common funcitionality
of all Osmocom.org projects, including OpenBSC but also OsmocomBB

The library currently includes the following modules:

bitvec, comp128, gsm_utils, msgb, select, signal, statistics, talloc, timer,
tlv_parse, linuxlist

msgb allocation error debugging had to be temporarily disabled as it depends on
'debug.c' functionality which at the moment remains in OpenBSC
diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index 82d7b02..99d8dd6 100644
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -38,12 +38,12 @@
 
 #include <openbsc/gsm_data.h>
 #include <openbsc/debug.h>
-#include <openbsc/msgb.h>
-#include <openbsc/tlv.h>
+#include <osmocore/msgb.h>
+#include <osmocore/tlv.h>
+#include <osmocore/talloc.h>
 #include <openbsc/abis_nm.h>
 #include <openbsc/misdn.h>
 #include <openbsc/signal.h>
-#include <openbsc/talloc.h>
 
 #define OM_ALLOC_SIZE		1024
 #define OM_HEADROOM_SIZE	128