Fix #623 - Add Quality selection options to ConfigTool for Audio/Video output

Fix #623. Easier configuration for output quality of video and audio by using a combo box to select. The bitrate determined for video will be based on the system resolution.

Tasks:
- [x] Add ComboBoxes for quality selection
- [x] Have ComboBox selection set qualities for Ogg Output
- [x] Have ComboBox selection set qualities for all plugins
- [x] Save ComboBox selection in profile and whether it should be used or has been overridden by manual quality entry
- [ ] Recompute video bitrate based on quality and resolution on record if "No Scaling"
- [x] Add config support for Ogg Icecast
- [ ] Add config support for WebM Output
- [ ] Disable config button and quality comboboxes when RAW Output is selected

Screen:
![quality selection](https://cloud.githubusercontent.com/assets/5759678/4958137/1ff74286-66ab-11e4-85b9-a0fe68cb225b.png)
You can use `self` to access class attributes as well.