This initial commit has the following pieces working:
  Maple: Grabner Disk Contact model (Hunt Crossley Contact + Coulomb Fric.)
         2-Disk Element Foot Contact Model

  Matlab: Grabner Disk simulation & animation
          2-Disk Element Foot Contact Mex function

I will need to do some minor surgery on the Mex function. This is somewhat
difficult to do, so I'm putting this all in Git before I break things!

Signed-off-by: mjhmilla <millard.matthew@gmail.com>
Testing Git - changed some white space.

Signed-off-by: mjhmilla <millard.matthew@gmail.com>
Testing a white space change in a branch

Signed-off-by: mjhmilla <millard.matthew@gmail.com>
Testing Git - commented a line.

Signed-off-by: mjhmilla <millard.matthew@gmail.com>