OS Detection

Implements automatic OS and architecture detection. This code has
been taken from the Qt repositories for Qt 5.4 (LGPL) and slightly
modified into the SubsurfaceSysInfo class.

Signed-off-by: Joseph W. Joshua <joejoshw@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Make system detection compile on Mac

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>