This function finds the projections that are equivalent via a 180 degree rotation and removes the duplicates.
uniqueByEquivalenceClass(p, unique.projections)the number of features in the original data.  This can be
obtained from a forest object via forest$params$paramList$p.
a list of projections from intermediate
steps of the FeatureImportance function.
unique.projections a list which is a subset of the input.