from  Benoît Perrot  <benoit@lrde.epita.fr>

	* src/vm/memory.hh, src/vm/mmu.hh, src/vm/cpu.cc,
	* src/vm/virtual_machine.cc:
	Implement reset() method.
	* src/vm/virtual_machine.hh, src/vm/virtual_machine.hh:
	Keep and reload the main offset of loaded program.