Repaired stripping of query strings from image URLs

As reported in #681, we are removing off query strings from image URLs. This is unexpected and unwanted behavior. This PR fixes that.

In this PR:

- Move `query` keys to `search` keys in `url` objects during `urlPolicy` formatting
    - As explained in #681, these are being silently thrown out since `url.format` expects `query` to be an object

Before:

![screenshot from 2014-03-29 06 03 38](https://cloud.githubusercontent.com/assets/902488/2558371/7d575e74-b743-11e3-841f-1324f6b27f67.png)

After:

![screenshot from 2014-03-29 06 09 58](https://cloud.githubusercontent.com/assets/902488/2558372/82443740-b743-11e3-9078-9acb90e5d3b3.png)

Fixes #681