Update to contrasts ANOVA

The contrast analyses are now aligned with the SPSS contrast analyses
(except for the polynomial contrast)
Added descriptive statistics option to ANOVA
Update to ANOVA

Added homogeneity test, estimates of effect sizes and the residual error
results to the ANOVA. Also, disabled options that are not essential for
now in the anovaform.
Update to ANOVA
Merge pull request #22 from raviselker/master

Updates to ANOVA