update rickshaw and d3 to latest versions

I ran into an issue using the Graph widget: Ruby's Time.now.to_i was not being translated properly for local time zones in Rickshaw.

A recent pull request added Rickshaw.Fixtures.Time.Local https://github.com/shutterstock/rickshaw/pull/239

The latest version of Rickshaw includes this update, and I went ahead and updated to D3 version 3 as well.

I updated my own versions locally, but thought this might help others as well.