- use more upstream hm code
- add call to memory check as done in vbox4
- add in principle all vbox devices and drivers
- avoid null pointer during VM startup (patch reported to vbox-devel list)
- avoid endless loop in usb root hub
Issue #2338
The main feature for this version upgrade is the use of the instruction
emulator (IEM) to speed up execution and less often the slow recompiler.
issue #2059
