include: reorganize headers file to include/osmocom/[gsm|core]

This patch moves all GSM-specific definitions to include/osmocom/gsm.
Moreover, the headers in include/osmocore/ have been moved to
include/osmocom/core.

This has been proposed by Harald Welte and Sylvain Munaunt.

Tested with `make distcheck'.

Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
diff --git a/tests/sms/sms_test.c b/tests/sms/sms_test.c
index 9d87b5b..f5d82b9 100644
--- a/tests/sms/sms_test.c
+++ b/tests/sms/sms_test.c
@@ -23,9 +23,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
-#include <osmocore/msgb.h>
-#include <osmocore/gsm_utils.h>
-#include <osmocore/utils.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/gsm/gsm_utils.h>
+#include <osmocom/core/utils.h>
 
 struct test_case {
 	const uint8_t *input;