Example data set for Rcontrast function

[sckott]

I added in an example data set and tree in the cotton.rda file in the /data directory

Here is the code to run it:

data(cotton)
Rcontrast(tree=cotton_tree, X=cotton_data)

I'll submit the pull request soon.

[sckott]

Sent a pull request at #3

[liamrevell]

I changed this to one data object, cotton, that is a list containing tree & data. Thus:

data(cotton) Rcontrast(tree=cotton$tree,X=cotton$data)

[sckott]

Thanks