[WIP] TNL-932: Add styling to Notes page.

@tymofij FYI.
@clrux FYI.

**sandbox:** http://tymofij.m.sandbox.edx.org/courses/edX/DemoX/Demo_Course/edxnotes/
> What do you mean?

![screen shot 2014-12-08 at 21 36 51](https://cloud.githubusercontent.com/assets/1247491/5345689/5f9825c4-7f22-11e4-827b-8b25b4b572ba.png)

Do we need additional styling for loading indicator?