GUI Overhaul (0.26.1-3 Alpha)

The first of these three updates (0.26.1) brings a number of changes to the GUI.  The first change you'll notice is the Java Look and Feel for the game has been changed to the Metal look and feel, but with a custom theme and more attractive icons for the window controls.  This change allowed me to eliminate a nearly 2 meg library file from the binary archive.  I still have plans to use that library for testing (it's quite good for assisting with the development of Java/Swing GUIs), so it's been moved into the source archive, similar to the SVG-Salamander library that's only used at compile time.

Most everything else affects the tool chooser dialog.  When you click on the paint swatches on the pages for blocks, masks, or furniture, it brings up a popup menu with a set of color choosing controls (the previous version would switch to the paint tab, instead).  The paint tab is quite different as a result of the change of Look and Feel.  It's default color chooser panel is now identical to the new one introduced and used by the popup mentioned earlier.

There's also many small improvements and bug fixes, mostly related to the GUI.

0.26.2 was an attempt to use the Itch app's manifest system to prevent the Windows launcher from being presented as an option under Linux.  This failed.  I do not understand why Itch is treating my computer as both a Linux machine and a Windows machine.  I don't want it doing that.

0.26.3 simply removes the Itch manifest file.