 improve documentation of methods.
 improve documentation of methods.

mne-tools/mne-cpp,chdinh/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,LorenzE/mne-cpp,LorenzE/mne-cpp