ENH: add peak getting API
FIXES + adde tests
whats new
revert unintended change
improve API and tests
cosmit
improve doc
fix vol source estimate API
improve tests, better erros, fixes

cosmit
cosmits
Merge pull request #984 from dengemann/find_evoked_peak

ENH/API: find evoked peak
Update evoked.py

cosmit
Verify comment is not None when checking its length
Merge pull request #988 from TalLinzen/evoked_none_comment

Evoked: Verify comment is not None when checking its length
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