Put everything in position to re-fork the verified App

Put everything in position to re-fork the verified App

If you pass "need_memory_introspection = false" to the Exploration
constructor, then the application is re-forked systematically instead
of taking snapshot that are then restored.

But it's still in progress, in the sense that the memory is still
introspected even if we don't need it. The network protocol still
needs to be changed so that the memory info are asked only if
"need_memory_introspection = true" and not otherwise.

For the time being, using reforks is very memory intensive for some
reason, and my computers gets to its knees when running the tests.
Until after the OOM killer saves me by cleaning stuff.