incanter/incanter — pull request #267 by johnchapin (2014-08-20 03:29:00+00:00)
Title: Follow sel :filter rename to group-on

In the `incanter.core/sel` function, the `:filter` keyword argument was renamed to `:filter-fn`, however `incanter.core/group-on` still uses the older argument name, effectively rendering it broken.

I discovered this while trying to follow along here: https://github.com/incanter/incanter/wiki/Statistics-Examples#linreg