introduce better interactions route /api/u for formatted interactions

Now you can use the `/api/u/:user` route to get formatted interactions. Here's what the new route looks like:

```
{ 
  interactions: [
    {
    parent: 8698858,
    time: 1417703735,
    type: "comment",
    title: "Orion flight test rescheduled for tomorrow",
    root: 8698587,
    id: 8699356,
    url: "http://www.nasa.gov/multimedia/nasatv/#.VIAwicl5V8F",
    by: "film42",
    text: "UDATE: 24-hr re-cycle."
    },
    {
    parent: null,
    time: 1417546348,
    type: "story",
    title: "Reflections on Trusting Trust (1984)",
    root: 8688983,
    id: 8688983,
    url: "http://www.win.tue.nl/~aeb/linux/hh/thompson/trust.html",
    by: "film42",
    text: ""
    },

  ...
```

Now @Baconbits and @qzcx can focus on rewriting the little bits of JS now.

Note: Pagination still works :)