Artist class added - draws bones!

I have left the text output untouched for now as I figure it will be
useful in finding any problems.

- Still need to finish of generalising the code to output the dominoes
at different sizes
- Artist should be a singleton. I started to do this but could not work
out how while still using the parent classes' constructor (it is a
derived class). Any ideas anyone?
- Need to change Artist.drawBone() so that it can draw bones portrait or
landscape
- Need a rewrite of a chunk of UI class in order that you can draw two
players hands without them appearing on top of each other.
- Need to work out what we do when we run out of space to draw more
bones!
- At the moment the bones on the table are simply being drawn over the
top of the previous ones with each play that is made. Not really best
practise I feel.