Improve paragraph control buttons, progress bar

Here're the changes

* Run button for each paragraph
* Showing progress bar now does not change paragraph's geometry
* Progress bar now 100% width of paragraph.
* Paragraph status displayed on paragraph control.
* Cancel button now moved into paragraph control.
* Show/Hide editor icon is very confusing with Show/Hide paragraph. Show/Hide editor icon changed to make it distinguishable
* Inside/outside of paragraph, padding, margin is really carefully adjusted. to not waste space.

A screenshot attached

![image](https://cloud.githubusercontent.com/assets/1540981/4350533/e09ae4e2-41ef-11e4-8f16-5e54525a17df.png)

Any feedback is welcome.
Ready to be merged.