Network graph fix (#909)
Created by: veprbl
Fixes #909. to be short: this patch turns this http://rghost.net/38755422/image.png into this http://rghost.net/38755441/image.png
In the ruby part it is just a new algorithm which properly places branches. I'm not a big ruby programmer, so this code may require some style fixing.
Javascript part replaces original lines placing with more practical github-like. This part may require some aesthetic revision.
All in all this patch still makes a good boost for gitlab's network graph usability.