idle.py -e file ...    -- to edit files
  idle.py script arg ... -- to run a script
  idle.py -c cmd arg ... -- to run a command
Other options, see also the usage message (also new!) for more details:
  -d       -- enable debugger
  -s       -- run $IDLESTARTUP or $PYTHONSTARTUP
  -t title -- set Python Shell window's title
sys.argv is set accordingly, unless -e is used.
sys.path is absolutized, and all relevant paths are inserted into it.

Other changes:
- the environment in which commands are executed is now the __main__ module
- explicitly save sys.stdout etc., don't restore from sys.__stdout__
- new interpreter methods execsource(), execfile(), stuffsource()
- a few small nits