Cleaned up one-interval/two-interval simulation code.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>
These files were not a good idea.  Getting rid of them.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>
Playing with params a little bit.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>