Revert "No longer maximize zenity windows. (Disabled due to a zenity bug in Debian Wheezy which leads to no text being visible.)"

This reverts commit 44c17bf53e1efe3cff1d477a4dfcf0b36796867a.
moved whonix_gateway/etc/xdg/autostart/whonixsetup.desktop to whonix_shared/etc/xdg/autostart/whonixsetup.desktop
No longer maximize zenity windows. (Disabled due to a zenity bug in Debian Wheezy which leads to no text being visible.); refactoring
fix autostart of whonixsetup on first boot of Whonix-Workstation