Removed DirectFB client as it is unmaintained

DirectFB support was in search of a maintainer for ages and
no longer compiles.
Since nobody stepped up get rid of this unused code once and for all.

.gitignore

@@ -93,7 +93,6 @@ cunit/test_freerdp
 client/X11/xfreerdp
 client/Mac/xcode
 client/Sample/sfreerdp
-client/DirectFB/dfreerdp
 client/Wayland/wlfreerdp
 server/Sample/sfreerdp-server
 server/X11/xfreerdp-server
@@ -142,4 +141,4 @@ packaging/deb/freerdp-nightly/freerdp-nightly-dbg
 .idea
 
 # VisualStudio Code
-.vscode
+.vscode