VirtualBox 4.0.16.75491

# The following items were fixed and/or added:
* VRDP: fixed screen corruption
* VRDP: fixed screen freeze
* ATA: fixed a possible crash during ATAPI passthrough with certain guests
* NAT: the interface stopped working after a lot of failed ICMP requests (bug #9371)
* Metrics: fixed potential problem with invalid access in guest metrics collection upon VM destruction
* Main: fixed incorrect framebuffer information after leaving the fullscreen mode with X11 guests, this lead to a scrambled preview window in the GUI for example
* VBoxSVC: fixed crash under rare circumstances (e.g. client crash)
* VMDK/VHD: fixed a possible corruption with host cache disabled when using snapshots under rare circumstances (bug #9749)
* OVF/OVA: fixed broken disk images on import under rare circumstances
* Mac OS X hosts: fixed the problem with duplicate packets when bridged to wireless interface (bug #9648)
* Windows Additions: implemented faster detection of logged-in guest users and stale sessions
* Linux guests: fixes for Linux 3.2