Updates tox/travis configurations for 3.6/pypy3.

Updates README.md with latest versions of python versions.
Ran locally on Ubuntu to verify install instructions.

Due to travis-ci/travis-ci#9542, we cannot use PyPy3 because
the version used in Travis CI is < 6.0.0 and has a defect
with decimals.

.travis.yml

@@ -5,7 +5,11 @@ python:
   - "3.3"
   - "3.4"
   - "3.5"
+  - "3.6"
   - "pypy"
+  # https://github.com/travis-ci/travis-ci/issues/9542
+  # pypy3 < 6.0.0 fails due to discrepancies with decimal...
+  #- "pypy3"
 install:
   - "pip install -r requirements.txt"
   - "pip install ."

README.md

@@ -49,20 +49,20 @@ of [tox](http://tox.readthedocs.io/en/latest/) with [pyenv](https://github.com/y
 Install relevant versions of Python:
 
 ```
-$ for V in 2.6.9 2.7.12 3.3.6 3.4.5 3.5.2 pypy-5.3.1; do pyenv install $V; done
+$ for V in 2.6.9 2.7.15 3.3.7 3.4.8 3.5.5 3.6.5 pypy2.7-6.0.0 pypy3.5-6.0.0; do pyenv install $V; done
 ```
 
 Note that on Mac OS X, you may need to change the `CFLAGS`:
 
 ```
-$ for V in 2.6.9 2.7.12 3.3.6 3.4.5 3.5.2 pypy-5.3.1; do
+$ for V in 2.6.9 2.7.15 3.3.7 3.4.8 3.5.5 3.6.5 pypy2.7-6.0.0 pypy3.5-6.0.0; do
     CFLAGS="-I$(xcrun --show-sdk-path)/usr/include" pyenv install $V; done
 ```
 
 Once you have these installations, add them as a local `pyenv` configuration
 
 ```
-$ pyenv local 2.6.9 2.7.12 3.3.6 3.4.5 3.5.2 pypy-5.3.1
+$ pyenv local 2.6.9 2.7.15 3.3.7 3.4.8 3.5.5 3.6.5 pypy2.7-6.0.0 pypy3.5-6.0.0
 ```
 
 At the time of this writing, on Mac OS X, you may have problems with `pyenv` and `pypy`.

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py26,py27,py33,py34,py35,pypy
+envlist = py26,py27,py33,py34,py35,py36,pypy,pypy3
 
 [testenv]
 deps=-rrequirements.txt