Update toyANOVA.R to use new `toy.anova` data

[norcalbiostat]

updated this code to reflect the changed format from the toy_anova to toy.anova data set in the openitnro package version 1.7.1 so the pdf image could be reproduced. I also added the axis labels on the bottom for groups I-III. After getting it to work locally, I used the 'suggest edit' on github itself to do this fork/PR. Hopefully I caught all necessary changes.