VMM: added support for OpenBSD guests

VMM: fixed a memory leak

Network: added Internal Networking (to directly wire VMs without using host interfaces and making the traffic visible on the host)

Network: fixed crash/hang at exit with TAP on Linux

Graphics: added support for additional custom VESA modes

Graphics: added support for VESA modes with y offset

VRDP: added support for remote audio (PCM encoding)

USB: fixed several potential crashes

USB: fixed revision filter matching

USB: fixed support for devices with integrated USB hubs