Removed rda_hastie.
Added the lda_schafer classifier along with unit tests

The actual classifier: Linear Discriminant Analysis (LDA) using the
covariance matrix estimator from Schafer and Strimmer (2005)
Added the lda_thomaz classifier along with unit tests

The actual classifier: Linear Discriminant Analysis (LDA) using the
covariance matrix estimator from Thomaz, Kitani, and Gillies (2006)
Focus is on HDRDA now. Removed RDA.
Updated MIT license and added LICENSE file. #25