Merged feature/css and related-docs

@shahabl, I merged your branch with the latest related-docs as in sebaslv/brackets-livedev2#1 but created this new pull request to get busykai:develop as the integration point.

recursive scan of @imports wasn't included in the merge. I'll take that from your original branch and manually merge it on my new implementation.
 

@busykai You can comment out the lines above (815-818) and uncomment the following segment, it still flickers on Chrome (on Windows).  Maybe there's some alternative way that can update this without flickering, if you have any suggestions please let me know.  Also if you just comment this part (and only keep the line 808, it does not refresh for chrome automatically, but it refreshes if you move your mouse over the browser window.  So as njx commented https://github.com/shahabl/brackets-livedev2/pull/2 if we can force a render we might be able to get it to work without flicker.