LW1949 1.1.0

Constrained corrected values for observed effects of 0% to a maximum of 10.5% and those for observed effects of 100% to a minimum of 89.5% in keeping with the intended application of Litchfield and Wilcoxon's (1949) Table 1.
Incorporated rounding in keeping with the true approach taken by Litchfield and Wilcoxon (1949)
- fitlinear() - default setting for argument constr set to c(0.0005, 0.9995).
- assessfit() - exclude records with expected effects < 0.005% or > 99.995%.
- correctval() - apply corrected values to expected effects < 0.5% or > 99.5%.
- LWestimate() - calculate Nprime as number of observations between ED15.5% and ED84.5%.
Introduced greater flexibility in plotting functions.
- plotDELP() - added argument grid.
- LWnomo1() - added argument ....
Extended predLines() and predLinesLP() to cover entire x-range.
Added citation (Adams et al. 2016).

LW1949 1.0.0