Add Pygment's elixir_example.ex to parser test case

Not all valid portions are currently parsed, but like Realistic.ex,
Pygment.ex is a good integration test for teh parser and lexer.
Use pygment example_elixir.ex.ex for Color Settings Page demo text

Add copy of pygment's example_elixir.ex.ex to the resources in `res` and
load it for the Color Settings page as it contains a test case for all
valid syntax according to @alco.
Update Color Settings screenshot

Update to current look of page using pygments example as demo text.
Lands #21, Pygments test case and demo text
Update change logs