WIP: first pass through BDF converter
ENH: read edf+ reader

Includes reader for EDF+. Renames to edf to include both bdf and edf+.
FIX: 2.6 compatibility COSMITS

cosmetics, remove unnecessary function.
Remove dictionary comprehension.
FIX: stim channel problem with BDF
ADD: stim_channel kwarg
ENH: API

Added n_eeg argument to handle channel info.
Added error messages
COSMITS: merged params dict with info dict
UPDATE

Combine the info dict construction into one method.
ADD: test for edf
ENH : more consistent measurement info between edf + fif (to be fixed cal/range in chs)
UPDATE cal and range, COSMITS: pep8 compliant
ADD: edf compatibility UPDATE: info dict: cal, range, unit_mul

Using the sample data provided by UCSD SSCN, added compatibility for
EDF+.
Updated the info dict to reflect the calibration factor, hardware
range, and unit multiplier. these are now used to calculate the gain
and D-to-A conversion.