New Recording UI

Fix #622

Implemented the layout discussed in the issue as well as some other changes listed below.

- New recording UI layout
- Buttons are now persistent
- All buttons now use only icons
- Custom icons consistent across all platforms (no system icons)
- Record button does not have to remain pressed (Stop button used to look pressed)
- Added "Leave record mode" button
- Output file now gets deleted if never recorded to

Screenshots:
Windows
![new recording ui](https://cloud.githubusercontent.com/assets/5759678/4585209/f94ef2e6-5002-11e4-9dc3-7ed62119d818.png)
![new recording ui 2](https://cloud.githubusercontent.com/assets/5759678/4585210/fb95dd26-5002-11e4-875d-b59d435550ca.png)