add basic qmp support

add basic qmp support

this add qmp socket to kvm process
and anew sub copied from vm_monitor_command:

vm_qmp_command ($vmid, $cmdstr, $nocheck)

$cmdstr could be a simple command to be executed, without argument

vm_qmp_command($vmid,"stop");

or a complex hash with arguments

$cmdstr->{execute}="eject";
$cmdstr->{arguments}->{device}="ide1-cd0";
vm_qmp_command($vmid,$cmdstr);

documentation about qmp commands is here
http://git.qemu.org/?p=qemu.git;a=blob;f=qmp-commands.hx;h=db980fa811325aeca8ad43472ba468702d4a25a2;hb=HEAD

Code must be polish a little more, but it's a start.

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>