Improve warning for out-of-data dataset
fix explained variance
cosmit
drop recentering
Merge pull request #992 from dengemann/fix_epxlained_variance

BUG: fix explained variance
ENH/API/MAIN radically improve sensor-topo API
py3k fix
cosmits
ENH: address discussion
Not up-to-date sample data warning: Cosmetic changes
Merge pull request #991 from TalLinzen/dataset_warning

Improve warning for out-of-date dataset
fix PEP
Merge pull request #990 from dengemann/improve-topo

ENH/API/MAINT radically improved and pythonic sensor-topo API