Removing extraneous Swift information from Features

Changes
* removing repeated information from Features page for Swift integration
* refactoring features.rst to 80 columns

Change-Id: Ib37e4476258cc4547d4a27847c89a9611bff05bc
Closes-Bug: #1376309
(cherry picked from commit eb529ca4f2dd153d494c4e02dd302998b3d6f43b)