Merge pull request #391 from dengemann/fix_plot_evoked_ylim

FIX: fix ylim kwarg
FIX: Dealing with tag=None in bad channels
Merge pull request #396 from Eric89GXL/raw-read-fix

FIX: Dealing with tag=None in bad channels

Thanks!
ENH: Better error for plot_evoked
ENH + FIX: correct logic

correct logic for plot-catch
ENH: initial commit

Adding native support for BTi
ENH: adding raw data reading

need to test this though
ENH: adding constants, refactoring reading functions
FIX: fix constants
COSMITS
ENH: read data debugged
- put stuff in functions instead of classes
ENH: intermediate commit, adding bti config file
ENH: writing config file code
ENH: edits on conversion class
MERGE
Undo rebase error
COSMITS: remove spurious snippets + tiny fixes
FIX: debug read user block
FIX: fix constants and read_userblock
FIX: constants and bti