Add B.C. Teachers' Labour Dispute (2014); resolves #13.

[ruebot]

• Remove existing dataset
• Add 4867 data
• Update example notebook
• Update README

[greebie]

Works well technically, but the sentimentality results gives something not very interesting:

I'll take a look at this tomorrow (on my way to class right now).

[ruebot]

Fair enough. I'll re-sample the dataset with shuf instead of tail.