Added a table that describes what OS and vBox versions are
supported in 7.0
Changed the Supported Operating System file name.
Moved the Supported Operating System section so it goes after
the Prerequisites section.
Change-Id: Ic5f9df89cdfb63a2b053225a4762b59c9c14959e
Closes-bug: 1497941
(cherry picked from commit a5c241c802)
7802ca8512