add example: spike inference on spikefinder datasets

[neuromusic]

add a script to examples/ that does the following:

1. loads data from one spikefinder dataset (see http://spikefinder.codeneuro.org) & fits it
2. tests the prediction against the spikefinder metrics (import spikefinder; spikefinder.score(y,y_pred) or something like that should work. see https://github.com/codeneuro/spikefinder-python)
3. compactly repeats 1 & 2 on all spikefinder datasets, generating a colorized table of results as in http://spikefinder.codeneuro.org

If the results are any good, consider submitting them to spikefinder, if it is still accepting new submissions :D