using google.auth (#62)

* First stab at using google.auth

Use new purpose-built package to generate sessions and handle refresh,
simplifying our code.

* Don't error if a connection method fails

* Re-enable token= access.

* Enable auth with Credentials

* Fixes

Plus text mode (see #52)

* Fix tests

(only three failures left)

* rerecord tests

* Better token hiding

* update dependencies for travis

* utf8 for py2 in test_core; drop py 3.4 on travis

(google requirememnts are not built for py3.4)

.travis.yml

@@ -5,7 +5,6 @@ language: python
 matrix:
   include:
     - python: 2.7
-    - python: 3.4
     - python: 3.5
     - python: 3.6
 
@@ -20,7 +19,7 @@ install:
   # Install dependencies
   - conda create -n test python=$TRAVIS_PYTHON_VERSION pytest requests
   - source activate test
-  - conda install -c conda-forge oauth2client
+  - conda install -c conda-forge google-auth google-auth-oauthlib
   - pip install vcrpy
 
 script: