Huge refactoring, working on main.js
Refactors code that updates a charge element
Finishes moving logic to the UI module
Improves efficiency of the UI module

Consolidates all retrievals of dom elements to one retrieval at
initialization of the module (if possible for the dom element)
Reorganizes files

Deletes old files, moves UI module to it's own file called view.js
Minor changes

Replaces hard coded radius values to use the "point_charge_radius"
constant