FIX prewhitening bug
update whats new
Merge pull request #1339 from dengemann/ica_fix_whitening_bug

FIX prewhitening bug
FIX: Refactor cov, projs, evoked, etc.
ENH: Move channels.py
FIX: Imports
FIX: Fix tests
FIX: Add to docs
EHN: add 2D image for evoked plots
API : fix API for evoked.plot_image
FIX : get rid of plot_evoked examples (use evoked.plot)
update what's new + reference
address comments
fix tests
add interactive SSP plotting for plot_evoked_image
misc
FIX: Fix test
STY: Test titles