Fixed fplist, subscripts (especially extslice) and enable Interactive
and Expression (single and eval). regrtest.py is now running.

Files:
modified: /branches/nowalker/src/org/python/antlr/InteractiveParser.java (try)
modified: /branches/nowalker/src/org/python/antlr/ExpressionParser.java (try)
modified: /branches/nowalker/grammar/Python.g (try)
modified: /branches/nowalker/src/org/python/antlr/GrammarActions.java (try)