Merge pull request #1 from karenc/master

Update example app and add userid to effective principals
Release version 0.6
Add a stub policy that authenticates against a fixed password

To use the stub policy, set "openstax_accounts.stub = true" in
development.ini

The default username is "test" and the default password is "password",
but can be overridden by setting "openstax_accounts.stub.username" and
"openstax_accounts.stub.password".  The profile can be set in
"openstax_accounts.stub.profile" in json format.

Close #2
Add travis support
Merge pull request #3 from karenc/stub-authentication

Stub authentication policy
Update profile api and run some integration tests on travis
Create sanction client in every request instead of storing it

The callback code could possibly fetch the wrong profile if the
authentication policy (and the sanction client) is shared between
different threads.  If there is only one sanction client and multiple
users trying to authenticate, we might end up using the someone else's
token to fetch a user's profile.

The solution is to not initialize the sanction client at configuration
time and to create a local client in the authentication code whenever we
need one.
Merge pull request #4 from karenc/integration-tests

Update profile api, add integration tests and fix the way sanction is used