qemu 2.0 support

[miurahr]

topics.

VNC: Setting the password via monitor command will not enable password auth as side effect any more. Use "qemu -vnc ${display},password" on the command line to enable password authentication.

QEMU can access NFSv3 shares directly from userspace using libnfs. The share must be configured to allow access from high-numbered ports

[miurahr]

#248 may be a result of testing on qemu2.0.