FIX MneExperiment._make_test():  TFCE
ENH Dataset.aggregate():  add `never_drop` argument
ENH Model:  add ._effect_to_beta
OPT glm:  Cythonize LMFitter
RF ND-ANOVA: separate classes for different model types
ENH glm:  unbalanced ND-ANOVA
STY/DOC
FIX Dataset.from_r()
ENH Dataset:  add .to_r()
TEST glm:  unbalanced 3 by 2 ANOVA with Adler dataset
SETUP:  Makefile
DOC:  changes
V:  0.4dev
FIX _opt:  allow input of different dtypes (Cython fused dtypes)