Bump version to 3.1.1

- Fix: Check that params to AuthorizationState are undefined before
  using an in-memory dict
- Fix: client_auth: unquote clientID and secret with Basic auth
- Deps: Update oic requirement to >=1.2.1
- CI: Update travis CI process

Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com>

Author: c00kiemon5ter

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name='pyop',
-    version='3.1.0',
+    version='3.1.1',
     packages=find_packages('src'),
     package_dir={'': 'src'},
     url='https://github.com/IdentityPython/pyop',