Auto-generate != pill colors based on tag text

I found this useful, it makes tags much easier to distinguish if you actually have a few. The background color is automatically generated from the content of the string. Thus far I have found them readable though I am sure it could be improved.

![grafana_-_welcome](https://cloud.githubusercontent.com/assets/219187/3756574/cd1e1842-182f-11e4-84a7-8c9a8ea84c80.png)