add wayland specifier to session names (#162)

Create a config option to force ly to add " (Wayland)" to session
names, as long as those names don't already contain the string.

src/config.h

@@ -89,6 +89,7 @@ struct config
 	char* term_reset_cmd;
 	u8 tty;
 	char* wayland_cmd;
+	bool wayland_specifier;
 	char* waylandsessions;
 	char* x_cmd;
 	char* x_cmd_setup;