- Added lookbehind propagation for the initial node; now, if the

- Added lookbehind propagation for the initial node; now, if the
  initial node is interested in what precedes it the automaton is
  given an initial all-consuming character class that determines it.
- Added verification of some node information invariants.  We now
  check that if a node expresses interest in what precedes it that
  information is available to it after assertion expansion.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@964 ce2b1a6d-e550-0410-aec6-3dcde31c8c00