UI Improvements

This is a substantial set of improvements to the Consul UI user experience and visual design.

Specifically, the goals were to:

- Make it more useable in larger deployments with hundreds of nodes, services
- Increase information density
- Performance improvements in large deployments

Here's a quick overview of some of the improvements in GIF form:

![foo](https://cloud.githubusercontent.com/assets/846194/3192843/e798962c-ecea-11e3-863a-35c0142516b4.gif)

There are still several UI improvements on the way, which in combination with these will be in the `0.3` release.