Configured Travis CI to run tests on Capture

Now when the `~/.janrain-capture` configuration file cannot be found the
tests will attempt to get the configuration from the following
environment variables: `APID_URI`, `CLIENT_ID`, and `CLIENT_SECRET`.
These environment variables have been encrypted and added to
`.travis.yml`.
Merge pull request #14 from janrain/topic/configure-travis-to-test-on-capture

Configured Travis CI to run tests on Capture