QtIFW

Include unistd.h where needed on Linux

This allows compiling with gcc 4.7.
For more information see: http://gcc.gnu.org/gcc-4.7/porting_to.html

Change-Id: I1b3b62fad3c44bdeb701d961297519a2057bf76e
Reviewed-by: Oliver Wolff <oliver.wolff@nokia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@nokia.com>
Reviewed-by: Tim Jenssen <tim.jenssen@nokia.com>