add read_ and write_evokeds functions
tests
FIX: Remove read_evoked use
Merge pull request #1 from Eric89GXL/read_write_evokeds

FIX: Remove read_evoked use
deprecate setno and change return types depending on "condition"
pep8 and replace Evoked with read_evokeds where appropriate
whats_new
whats_new
Merge pull request #1244 from adykstra/read_write_evokeds

STY: replace read_evoked and write_evoked with read_evokeds and write_evokeds