Deprecate --glx-swap-method

Setting glx-swap-method to value other than "undefined" and "buffer-age"
could potentially cause rendering problems. So remove them, the meaning
of the remaining options can be more precisely captured by "use-damage",
so create a new option under that name.

--glx-swap-method is deprecated in favor of the new option --use-damage.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

compton.sample.conf

@@ -70,8 +70,8 @@ invert-color-include = [ ];
 # GLX backend
 # glx-no-stencil = true;
 # glx-no-rebind-pixmap = true;
-glx-swap-method = "undefined";
 # xrender-sync-fence = true;
+use-damage = true;
 
 # Window type settings
 wintypes: