GUI

A functioning GUI is added.
GUI displays potential using color.
(Standard Java GUI dependencies, uses javax.swing & java.awt packages)
Possible updates may occur later to add text fields, but for now, edits
to GUI must be made directly to java file.
Revert "GUI"

This reverts commit d13b497f6875d5497acc5b8594f5501beec4812c.
Revert d13b497..f346db8

This rolls back to commit d13b497f6875d5497acc5b8594f5501beec4812c.
Revert 6b88e9f..7e20150

This rolls back to commit 6b88e9faa1cdad33faef5761b1e12be8651f3bce.
Revert d13b497..3a8b510

This rolls back to commit d13b497f6875d5497acc5b8594f5501beec4812c.
Updated GUI

Now has colors (actually makes a difference when attempting to compare
potentials, easier than grayscale)
GUI also works from command line now in addition to Grid.java