New Useful G-Code Function

Add additional functions for working with the G-Code
G-Code Viewer Improvements

Improvements:
-Everything now works
-Non-extrusion moves are now displayed as lines
-Moves with extrusion are displayed as filled boxes
-Extrusion lines now have a height based on layers and width determined
by the volume of the extrusion
-Moves will change color if a potential fault is detected in them
Added Empty Handlers

Added empty handlers so that the parser does not throw exceptions for
unhandled codes.
Added Change Layers Functionality

You can now change how many layers are displayed by using the slider to
the right of the jMonkey Panel
Merge branch 'GUI_Dev' of https://github.com/NeuronRobotics/NrConsole into GUI_Dev