Demos Organized, New Stimuli

The Demos have been renamed to include a short description of their purpose, and now include individual readme files that better explain their purpose. There is now a demo4.py file, however it has not had any significant work done as of yet. There are also screenshots of the tasks.
Demo3 now has two versions, demo3a and demo3b. A is unchanged from the old version, B now reads the stimuli filepaths from a csv list.
There are a bunch of new stimuli, basic shapes in a few common colors. There are master .svg files and .png files for use in tasks.

-mm