* src/qemu/qemu_monitor.h, src/qemu/qemu_monitor.c: Add new APIs
  qemuMonitorSaveVirtualMemory() and qemuMonitorSavePhysicalMemory()
* src/qemu/qemu_driver.c: Use the new qemuMonitorSaveVirtualMemory()
  and qemuMonitorSavePhysicalMemory() APIs