STM: take a shallow snapshot for the first proof step

this way it can be directly sent to a slave with no further manipulation

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16836 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: delegate proofs to slaves only if they are not trivial

Still too simple and not configurable

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16837 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: avoid "kill 9 pid" if we know the slave died

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16838 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: number of slaves passed by the command line

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16839 85f007b7-540e-0410-9357-904b9bb8a0f7
Regression test suite for STM

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16840 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: add options to disable fallbacks to ease regression testing

STM falls back to local, lazy, evaluation if the slave dies badly or
if there is a marshalling error.  Both things should never occur, but
is nice to have the system recover if a bug pops up.
Nevertheless during regression testing these fallbacks should be
disabled not to hide a new bug.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16841 85f007b7-540e-0410-9357-904b9bb8a0f7
CoqIDE: when jumping to an error also move the cursor

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16842 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: if -coq-slaves off really imitate the old CoqIDE

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16843 85f007b7-540e-0410-9357-904b9bb8a0f7
STM: understand -coq-slaves-opts extra-env=VAR=val

In this way one can set an env variable for the slave, like the
socket used by ocamldebug to talk remotely to a process

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16844 85f007b7-540e-0410-9357-904b9bb8a0f7
A shallow copy of a pre_env does not contain the vm cache

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16845 85f007b7-540e-0410-9357-904b9bb8a0f7