Improper modularity implementation

[hailstorm75]

One of the core goals of this project is to provide a modular tool - it's in the name.
However, the implementation is horrible.
Adding a new plugin is overly complicated and even broken.
Thus, the approach must be rethought and reimplemented.

The resulting change might sacrifice the ability to easily replace the GUI of the tool; however, there is little to no reason for adding such flexibility. The primary focus should be extensible functionality.