Added Affix style to halloToolbarFixed

The halloToolbarFixed position changes from absolute to fixed once it begins to go out of view. At the end the editable element it snaps back to absolute. The toolbar is visible at all times even when the editable element is very large: Please see examples/fixed.html

**Before Toolbar is affixed:**
![Screen Shot 2013-01-23 at 11 29 12](https://f.cloud.github.com/assets/99309/89752/25bfa52c-6550-11e2-945c-3cca62c8b780.png)
**After Toolbar is affixed:**
![Screen Shot 2013-01-23 at 11 21 40](https://f.cloud.github.com/assets/99309/89746/9c31a4b8-654f-11e2-96a5-645067196482.png)