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/handover_decision.c b/openbsc/src/handover_decision.c
index b37cecd..efafca6 100644
--- a/openbsc/src/handover_decision.c
+++ b/openbsc/src/handover_decision.c
@@ -25,14 +25,14 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#include <openbsc/msgb.h>
+#include <osmocore/msgb.h>
 #include <openbsc/debug.h>
 #include <openbsc/gsm_data.h>
 #include <openbsc/meas_rep.h>
 #include <openbsc/signal.h>
-#include <openbsc/talloc.h>
+#include <osmocore/talloc.h>
 #include <openbsc/handover.h>
-#include <openbsc/gsm_utils.h>
+#include <osmocore/gsm_utils.h>
 
 /* issue handover to a cell identified by ARFCN and BSIC */
 static int handover_to_arfcn_bsic(struct gsm_lchan *lchan,