Further tidying of script
Further tidying of script

A number of extra comments were added to help explain code structure;
several variables were renamed to make code more pythonic: struct (as in
MATLAB structured arrays) renamed to dict; matplotlib path effects used
to add a white outline to annotation text for improved visibility; code
slightly restructured so that analysis occurs before plotting.

Fig. 3 is still generated correctly; some minor differences due to
nPerm=1000 (rather than 10,000).

DavisLaboratory/prosperiti