terminal: Window operations

Implement OSC 1 (set window title), and some basic CSI t window
operations.

Signed-off-by: Callum Lowcay <callum@callumscode.com>
diff --git a/clients/window.c b/clients/window.c
index efd8fa4..98bc53a 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -1208,6 +1208,19 @@
 }
 
 void
+window_set_title(struct window *window, const char *title)
+{
+	free((void*) window->title);
+	window->title = strdup(title);
+}
+
+const char *
+window_get_title(struct window *window)
+{
+	return window->title;
+}
+
+void
 window_damage(struct window *window, int32_t x, int32_t y,
 	      int32_t width, int32_t height)
 {