generative text notes

[shiffman]

need to add explanation for:

• context free grammar that pulls from source text
• wordnik API and combining with CFG
• twitterbot and combining with markov/CFG/etc
• reference and thank http://tinysubversions.com/2012/05/how-i-built-metaphor-a-minute/ for wordnik / twitter
• links and reference material for RiTaJS