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/paging.c b/openbsc/src/paging.c
index 91de702..7c3750d 100644
--- a/openbsc/src/paging.c
+++ b/openbsc/src/paging.c
@@ -40,7 +40,7 @@
 #include <assert.h>
 
 #include <openbsc/paging.h>
-#include <openbsc/talloc.h>
+#include <osmocore/talloc.h>
 #include <openbsc/debug.h>
 #include <openbsc/signal.h>
 #include <openbsc/abis_rsl.h>