TEST FIX:  load.fiff
ENH Notifier:  Log when entering notification
ENH Report:  add .sign()
DOC:  add recipes section
PROFILE:  data to profile lm functions
STY opt:  _lm_ss_res() -> lm_res_ss()
OPT opt:  extract lm_betas()
OPT opt:  define yi
DOC opt
API:  Model.Xsinv -> Model.xsinv
ENH:  NDVar.residuals() method
OPT opt:  cdef lm_betas() as void
DOC:  changes