various design improvements per #11540

This PR includes the new tree design from issue #11540 (a merged version of @eladnova and my mockup) and various other smaller changes and improvements like:

- darker form labels for more contrast
- improved icon position in the tree
- other padding optimizations (mostly in the tree)
- font color changes for better contrast


BEFORE:
![voila_capture 2014-06-25_05-59-04_nachm](https://cloud.githubusercontent.com/assets/482184/3387915/951871ae-fc82-11e3-9943-0b09526611ee.png)

AFTER:
![voila_capture 2014-06-25_05-58-24_nachm](https://cloud.githubusercontent.com/assets/482184/3387920/9eed505a-fc82-11e3-86d3-f7a0d3572a92.png)