Added reminder for shaped windows

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403529

TODO

@@ -24,6 +24,7 @@
  * Add name -> keysym and name -> scancode lookup functions
  * Fix building haptic system on win32
  * Add always on top window styles
+ * Add video modes that have an alpha channel?
 
 Wish list for the 1.3 development branch:
 http://bugzilla.libsdl.org/