update README/help, call it v0.13

fix reference link, `cli` → `__main__`, call it v0.12

v0.11… let's finally call it “beta”

I'm really bad at building working Python packages 🤦🏻‍♂

(ping dlenski#28)

fix setup.py, add description.rst, and call it v0.10.1… so we can upd…

…ate PyPi (fixes dlenski#28)

lxml 3.5 is fine (ping dlenski#19)

fix tests to match latest version of provision