ChannelIndex.channel_names is now 'U' instead of 'S'

[samuelgarcia]

No description provided.

[samuelgarcia]

This need to merged before #824

[samuelgarcia]

@MarinManuel @JuliaSprenger : I prefer this fix for channel names.
The 'U' is now official.

[JuliaSprenger]

I think there are a still a number of places in the code, where 'S' is used instead of 'U', e.g.

python-neo/neo/io/brainwaredamio.py

Line 141 in fce4227

channel_names=np.array(['Chan1'], dtype='S'))

These are not affecting the functionality, since the type is anyway converted later, but maybe it would make sense to systematically replace 'S' by 'U' also in all non-relevant places?

[samuelgarcia]

I think I already fix the brainwaredamio no ?
Test are passing so I think there is no channelindex.channel_names with 'S' anymore.
Each object read by IOs are tested for there types and dtypes normally.
What do you think of this solution ?

[JuliaSprenger]

Yes, you are right, I missed that one. Looks good to me!
Thanks for the fix.