Improvements + correction to info bubble.


-Info bubble border sharpening:
Before sharpening
![image](https://f.cloud.github.com/assets/4847382/1490951/82bac1d8-47a1-11e3-83b5-a530bf7ded90.png)
After sharpening
![image](https://f.cloud.github.com/assets/4847382/1490922/43bdf244-47a0-11e3-81da-1bdd09272d2c.png)

-Removing unnecessary header information in preview and node tooltip

-Code cleaning