Time sliders

Issue https://github.com/AUTUpStageTeam/UpStage2013/issues/120
- Added two sliders and 4 buttons for stepping up and down by 1 second
- Use unicode symbols instead of words to identify buttons (I can't put the symbols in the centre perfectly; this is the best I can do)
- Volume slider is now vertical

![screen shot 2556-10-05 at 19 03 38](https://f.cloud.github.com/assets/717270/1274242/336185a4-2d84-11e3-8d7a-dae04f151b09.png)