layout: Keep kind metadata in loaded layouts

It will come useful for applying per-kind styling later without having to give each layout a new stylesheet

src/server-context-service.h

@@ -34,7 +34,7 @@ G_BEGIN_DECLS
 typedef struct _ServerContextService ServerContextService;
 
 EekboardContextService *server_context_service_new ();
-enum layout_type server_context_service_get_layout_type(EekboardContextService*);
+enum squeek_arrangement_kind server_context_service_get_layout_type(EekboardContextService*);
 
 G_END_DECLS
 #endif  /* SERVER_CONTEXT_SERVICE_H */