Check column names before plotting test data in model plotting functions #276
Description
It turns out that if your geom names in your test data vect object are "x" and "y", you end up getting duplicate column names when trying to convert that vect back to a data.frame. This causes all of the plot.enmtools.model functions to barf when plotting test data, since they have two x columns and two y columns. We need to put in a check for that and rename where needed.