* VMM: reduced IO-APIC overhead for 32 bits Windows NT/2000/XP/2003 guests; requires 64 bits support (VT-x only; bug #4392)
* VMM: fixed double timer interrupt delivery on old Linux kernels using IO-APIC (caused guest time to run at double speed; bug #3135)
* VMM: reinitialize VT-x and AMD-V after host suspend or hibernate; some BIOSes forget this (Windows hosts only; bug #5421)
* VMM: fix loading of saved state when RAM preallocation is enabled
* BIOS: ignore unknown shutdown codes instead of causing a guru meditation (bug #5389)
* GUI: never start a VM on a single click into the selector window (bug #2676)
* Serial: reduce the probability of lost bytes if the host end is connected to a raw file
* VMDK: fix handling of split image variants and fix a 3.0.10 regression (bug #5355)
* VRDP: fixed occasional VRDP server crash
* Network: even if the virtual network cable was disconnected, some guests were able to send / receive packets (E1000; bug #5366)
* Network: even if the virtual network cable was disconnected, the PCNet card received some spurious packets which might confuse the guest (bug #4496)
* Shared folders: fixed changing case of file names (bug #2520)
* Windows Additions: fix crash in seamless mode (contributed by Huihong Luo)
* Linux Additions: fix writing to files opened in O_APPEND mode (bug #3805)
* Solaris Additions: fix regression in guest additions driver which among other things caused lost guest property updates and periodic error messages being written to the system log