Ignore Filter

This adds a textfield where you can specify a pattern that will be ignored.

Haven't used Ember before so please let me know if there's a better way I could have done this :)

![screen shot 2014-05-05 at 3 57 04 am](https://cloud.githubusercontent.com/assets/133809/2877140/718380a0-d444-11e3-9ba5-a04e81cdd8e6.png)