ENH: add EvokedArray class
mostly tests, some function changes
addresses Alex's comments
whats_new
python_reference
function and class exposure
more for Alex, and unrelated authorship
indentation and pep8
move create_info to mne.io.meas_info, and related
missed one create_info import
move _kind_dict to mne.io.meas_info, and related
addresses Eric's python_refence comments
more input checking, and python_reference
Merge pull request #1345 from adykstra/EvokedArray

ENH: add EvokedArray class