Graphics: Add proper tooltip

Add: Proper look to the tooltip.
Graphics: Overhaul button

Add: Better and more "click-me!" graphics to the standard button.
Graphics: Overhaul minimized taskbar button

Add: The taskbar button for minimized windows now shows the complete outline of the non-minimized button.
Graphics: Add proper disabled state to buttons

Add: Most of the buttons now actually look like they are disabled when they are.
Fix FileAddAction with root path

Fix: The FileAddAction can now add files to the root file of a file system properly.
Add root file tests to file action tests

Add: The File*ActionTest tests now check whether performing their operations on files that are children of the root file of a file system works as intended.
Add occupied file name check to FileAddAction

Add: The FileAddAction now throws an IllegalStateException if the file name for the file to add is already occupied by another file.
Add: The FileCreateProgram now fires a OccupiedFileNameEvent if the same thing happens.
Update and clean up tests

Add: Update the tests to support the latest FileAddAction change (occupied file name errors).
Fix: Generally clean up the file tests.
Add daily log file rolling

Add: The log files are now rolled daily.
Split desktop window mechanisms and desktop programs

Add: The DesktopWindow class represents a window on the desktop. The DesktopProgramWindow class extends DesktopWindow and adds functionality that is important for desktop programs.
Remove: The DesktopProgramManager module is no longer required since the responsibilities are separated.
Remove shell ui resources

Remove: The twl theme files and images for the shell (it is no longer required since there won't be a shell).
Overhaul ui and clean up resources

Add: Ovheraul the ui components of the game.
Fix: Clean up the twl resource files.
Swap state and descriptor arguments on DesktopProgramWindow constructor

Fix: Swap the GraphicsState and DesktopProgramDescriptor arguments on the DesktopProgramWindow constructor.
Add close listeners to DesktopWindow

Add: The DesktopWindow class now accepts close listeners that are called when the window is removed from the desktop ("closed").
Add default size to desktop windows

Add: DesktopWindows can now have a default size. The windows will have that size when they are added to the desktop ("open").
Add desktop window centering

Add: DesktopWindows are now centered when they are added to the desktop. If a new window has a "logical parent" window, it is centered relatively to that window.
Add mediators for desktop windows

Add: The DesktopWindowDefaultSizeMediator and the DesktopWindowCenteringMediator take care of defaulting the window size or centering windows on the desktop.
Remove: The ugly defaultSize and logicalParent properties of windows. They are replaced by the mediators.
Use FileAction implementations instead of abstract interface

Add: Use the FileAction implementations instead of the abstract FileAction interface because the implementations might document exceptions on the EXECUTE method.
Add proper file exceptions

Add: Proper exception classes for the file actions and factory methods of these file actions.
Fix: The KnownFileSystem.MOUNTED.set() method throws an IllegalStateException instead of an IllegalArgumentException.
Rename FileCreateProgram.OccupiedFileNameEvent to OccupiedPathEvent

Fix: Rename the FileCreateProgram.OccupiedFileNameEvent class to OccupiedPathEvent because the exception thrown by FileAddAction is also called OccupiedPathException.