Adding profile comments search

You can now search for comments on a user's profile page.
Blessed be to @james-rodgers who made the endpoint for this.

It is behind a switch in case we have performance issues and the endpoint hadn't made it to PROD yet.

![commentssearch](https://cloud.githubusercontent.com/assets/31692/3343176/1090f4cc-f89c-11e3-877f-561bd1d19900.png)

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![Found](http://media1.giphy.com/media/Trt8Fw4KfzVJu/giphy.gif)

On mobile I'm wondering if that should be half a gutter instead (because of smaller outer margins). Worth a check.