Moved helper macro to a discrete include file.

To help reduce code duplication and also 'kitchen-sink' includes
the ARRAY_LENGTH macro was moved to a stand-alone file and
referenced from the sources consuming it. Other macros will be
added in subsequent passes.

Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

ivi-shell/ivi-shell.c

@@ -45,6 +45,7 @@
 #include "ivi-application-server-protocol.h"
 #include "ivi-layout-export.h"
 #include "ivi-layout-private.h"
+#include "shared/helpers.h"
 
 /* Representation of ivi_surface protocol object. */
 struct ivi_shell_surface