add segment.io to impactstory.js

it's throwing "Uncaught RangeError: Maximum call stack size exceeded" frequently (though
not always). This seems unrelated to the Segment.io stuff, as it persists even when I
disable Segment.io.
Fix recursion error by including our own jquery with widget.js

This will cause slower load times, when the page already has our same version
of jQuery loading already. But avoids messy recursion errors it seems, and is
way easier to understand.
Move most of impactstory.js into $(document).ready block. Remove Segment.io calls.

Hopefully this will cure recursion errors?  Segment.io needs access to window.analytics to run
it seems (see https://github.com/segmentio/analytics.js/issues/103 and
https://github.com/segmentio/analytics.js/issues/39). Seems bad to be mucking about with this
since whoever is embedding us may be counting on it. I think we'll need to log everything on our
side, which thankfully isn't that tough.