WIP/API/ENH: create epochs in ICA space

Here I propose two new convenience methods for the ICA class which
allow useres to directly create epochs in ICA space without previous
export to Raw. This addresses #319
FIX: remove unsuited score func test cases.

Closes #315.
ENH: realizing epochs.sources_as_epochs_from_epochs

+ adding to example
ENH: addressing recent discussion
ENH: ... hwat's new
ENH + FIX: addressing discussion + add picked data
CLEANUP example
ENH: take advantage of Epochs ch_names property
COSMITS
FIX: example
ENH: call pick_types correctly
CLEANUP
Merge pull request #540 from dengemann/ica_epochs

WIP/API/ENH: create epochs in ICA space