Add a copy of the MPL and put tests in Public Domain

As suggested on https://www.mozilla.org/MPL/headers/
Merge pull request #8 from fmarier/add_licensing_info

Add a copy of the MPL and put tests in Public Domain
Add jshint to the tests (fix #6)

This is inspired by the test of the same name in browserid-local-verify
(https://github.com/mozilla/browserid-local-verify/blob/404bdcd158094aaaeb412b8eb0263243c79f8b92/tests/jshint.js) and enables all of the checks that pass.
Merge pull request #10 from fmarier/jshint

Add jshint to the tests (fix #6)
Make the InvalidAgentInterval configurable
Pass the missing BLOCK_INTERVAL_MS to the ip_record
Check for blocks against the right interval
Make the now() function configurable to facilitate testing
Copy the retryAfter function from email_record.js
Add unit tests for ip_record.js