* Redid the Main application window (nothing fancy, just something that fits specification).

* Added Browse/Save option for tree.cfg location path
* Added developer mode - The possibility to create and edit a list of mods and their corresponding parts for reference within the application. Saves the data to file (and loads).

* The ModCollection class created from the devmode stuff is going to be essential for figuring out what parts correspond to what mods in the final application.