Progress on Visual Elements

After studying Ross Hatton's Robot Drawing Tools package, I decided to
try creating my own visual tools by combining robot links with 'Joints',
which ideally can control the angles/elevation of each component
separately. I may refactor the 'structs' into classes, since I believe
it is easier to make links as handle objects. Although I am using URDF
for ideas on how to structure the system, I am no longer planning to use
URDF directly, as its structure is better suited for 3 dimensional
representations.

Successful implementation of matrix rotation for visual elements,
although I need to work out how this works recursively with joints.
thrown into the mix.

After working out visual elements, links, and joints, I should be able
to modify the display such that update functions will redraw the system
in a way that makes sense.