Source files clean up

* Split DecoratorFinalFantasyFrame class interfaces into their own
respective source files.

* Introduce public header exports file.
Refactor MouseButtonEventListener

This class is now being modeled after gui/UIEventListener & friends;
it looks like my implementation coincidentally matches libRocket's
very well for the most part.

* Resolved crashing issue by removing static declaration; I wonder
why the example I borrowed it from felt it was necessary?
Introduce initial DataViewList styling & template
Code styling (indention, braces, etc.)