Tb montage enh

Adds montage option to edf and brainvision modules to provide standard import of electrode points.
Adds fiducials to the montage.
Organization of transformation functions into the transformation module.
the EEG locs stored in a `Montage` should already be in head space. I agree with @dengemann that it makes more sense to use the fiducials to transform the HPTS file into head coordinates when you read the file, not when you apply the montage.