Adding the ability to get terms with a date (bug 932577)

https://bugzilla.mozilla.org/show_bug.cgi?id=932577

The date is optional and no logic is performed on the zippy side, the
client have the responsibility to deal with the validity/expiry of
terms given that date.
Merge branch 'master' of https://github.com/mozilla/zippy into 932577-adding-terms
Merge pull request #39 from davidbgk/932577-adding-terms

Adding the ability to get terms with a date (bug 932577)