adding new UI file
removing nanogen_4.ui
updating MVC modules
updating UI files
adding __docstring__ setting
adding constant for van der Walls distance
updating __docformat__ setting
adding new property setters and getters for element1, element2, Lx, Ly
adding check for an outpath of None
renaming image files
adding outpath parameter
adding new property setters and getters
minor edits to use new outpath parameter
updates to use outpath parameter
updates and additions to UI and MVC design pattern