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/src/vty/vty.c b/src/vty/vty.c
index c1a9b3a..a1f0304 100644
--- a/src/vty/vty.c
+++ b/src/vty/vty.c
@@ -16,7 +16,7 @@
 #include <osmocom/vty/vty.h>
 #include <osmocom/vty/command.h>
 #include <osmocom/vty/buffer.h>
-#include <osmocore/talloc.h>
+#include <osmocom/core/talloc.h>
 
 #define SYSCONFDIR "/usr/local/etc"