Improvements to first workshop file.

Removed image of shapes reference including refernce to missing png file.
math -> maths
Put in a warning about saving your work. Cylde: is this needed in the version they are using ?
staff -> demonstartor
removed camel case variables/functions
Removed a print from the string concatenation example. There is a section explaining print directly
after I though this was a little confussing.
Added spaces between items in functions i.e. my_func(a,b,c) -> my_func(a, b, c) this to me makes
code much clearer.
Print keyword -> Print function once.

TODO:
Traceback has wrong version of python. Clyde: Can we add in the correct one for the version they
are going to use?