Added text and images for the OF Plugin chapter.

I'm only tweaking Sujatha Joseph's original commit:
* fixing so it will build
* removing what seemed like 3 extra copies of the whole section
* making images fit on pages

Change-Id: I9c4f373f488f2d9c4a9204013f8afcb269aafeda
Signed-off-by: Sujatha Joseph <josephs@brocade.com>
Signed-off-by: Colin Dixon <colin@colindixon.com>
Merge "Added text and images for the OF Plugin chapter."