e.g. further improve subprocess interrupt, exceptions, and termination.
2. Remove the workarounds in PyShell.py and ScriptBinding.py involving
   interrupting the subprocess prior to killing it, not necessary anymore.
3. Fix a bug introduced at PyShell Rev 1.66: was getting extra shell menu
   every time the shell window was recreated.

M PyShell.py
M ScriptBinding.py
M rpc.py
M run.py