Doc:Updated information about tested platforms.

-Adding Ubuntu 11.10 32-bit as a tested platform.
-Updated Windows 7 and 8 compiler versions
-Updated link to MinGW download

Change-Id: If2acc11f044ad4623cb035eaefae9ba370f5c5a6
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>