Merge pull request #400 from dengemann/fix_plot_evoked_ylim

ENH: more liberal ylim handling
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
FIX: constants, userblock
FIX: another round
ENH / API: distributing code over submodule