Hotfix/2034 knowledge map cant be scrolled

For #2034 - "Knowledge map can't be scrolled" - this is the initial fix to allow user to scroll horizontally if the contents of the map is more than its container's width. 

I also modified the formula to compute for the `margin-left` attribute of the container and to set it's `overflow` attribute to `scroll` as needed.

I have tested this with browser size of "1024 x 768" on Chrome v34.0.1847.131, Firefox v29.0.1, and Safari v7.0.3.