Add a utility for the WeThePeople API.

1) Changed jade indenting from spaces to tabs (sort of annoying to deal
with spaces for indenting)
2) Added a wethepeople class which has 1 method (for now),
getPetitions(), which returns the JSON as an object from the API
3) Added unit test for wethepeople (requires jasmine-node -- can be
installed with npm jasmine-node, and run with jasmine-node spec/ in the
root folder)… Want to integrate with Travis CI for continuous checks
when committing.
4) Added error.jade for error handling