Replace nose (unmaintained) with nose2, remove Python 3.5 from CI (EO…

…L), add warning to slow test, call it v0.14 for real this time

Potential FIXMEs for nose2?  It has some frustrating differences from nose
(https://docs.nose2.io/en/latest/differences.html), including:

- lack of 'assert_[a-z]' or 'assert[A-Z]*' functions, except as
  *methods* of unittest.TestCase subclasses
- inability to set '--verbose' when running as 'python setup.py test' (I
  tried adding '[unittest]\nverbosity = 2' to setup.cfg...  does nothing,
  unlike putting it in unittest.cfg, which works but only when running
  explicitly via 'nose2' CLI)

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