[Spitbol] Fixes

- A bug in ensure "remembered" the first rest in the VM's life
- Break, Span and the like consumed one character too many
- Most recent parameterized parser construction words didn't take
  wrapped args. Fixed for token, exactly-n and the like. Args which are
  parsers can't be wrapped. range-pattern's string arg won't be taken
  wrapped for the time being. It is the only known exception.