Eq plugin

Initial pull request for the native EQ plugin, #1376 

![image](https://cloud.githubusercontent.com/assets/7412852/5425560/4ecbfbbc-8314-11e4-9a7e-334e7910f87e.png)

Also, maybe there could be tooltips/textfloats when moving the number
widgets on the display - ones that show freq and gain both?