v0.8.3

- Two new models: onlyx (x + x^2) and onlyy (y + y^2). Also included in
compare() and in compare(... , plot=TRUE)
- Arbitrary data points can be plotted in plotRSA - i.e., you can plot
a fit with existing regression weights, and still plot raw data points.
See plotRSA() --> points(data=???)
- plotRSA --> points(value="predict") now also works in interactive
plots (type="i")
- The hull in plotRSA now is much smoother and lies on the surface
(before, long connection lines cut through the surface)
- print.RSA now prints the regression coefficients including
standardized beta weights, and can print summaries for a submodel:
print(r1, model="RR")