Fix png font size, add SVG, and use the file naming convention for other SGP types (use.sgp = x).
add CairoSVG to produce svg goodness of fit plots (experimental)
Plot separate norm group analysis plots for EOCT subjects
Update man page to SVG output
Merge pull request #658 from adamvi/master

Changes to gofSGP for EOCT courses and png/svg output options