v0.4.0 - Editor fully self-contained

This release covers two major points:

• Editor is now fully self-contained; Both in terms of user-interface, and in terms of loading the data
• Object property display

The separation of a graphical display and a text-based control did not work in the long run. A simple support for controls (such as labels, buttons, combo-boxes) was created and then hooked up for interacting with the editor.
This makes it much easier for the user (mouse-only interaction), and also allows for better representation - best seen with the texture selection for instance. Future additions may also have direct interaction with the map.

The browser support was dropped in this release. On the display side, performance was dropping and having a server/client concept for the editor at this stage was not necessary. This point also dips into the next point: Dropping the server/client concept alltogether.
Putting the access to the resources into the editor makes it a standalone application. This integration also drops the support for "projects" - i.e., handling multiple editions at once. The application is now started for one set of files, and these are worked on.

Finally, many of the properties of level objects were documented meanwhile, and the editor can display most of this information. At the moment, this is just a rudimentary display of numbers. Further iterations will allow to modify them.