Improved appearance of GUI.

We can draw colorfades now and also fill triangles.
Fixed access modifiers for resizeTo and moveTo.
Added the secret-option to Editable.
Moved Align and Orientation enums to enums.h.
Added alignment attribute to Label.
Moved theme-constants to source-file.
Bugfix in Panel: don't assume that we have a parent.
Added keyboard-interaction to ComboBox.
Fixed focus-handling in Window.
Fixed permissions of winmng-shm-file and winmng-device.
Make desktop active if there is no active window yet.
Added a real GUI login application.