Final head of the former 2.0 branch

1. 2cb176f Correct docstring about return value when group didn't participate in match by Andrew M. Kuchling · 25 years ago
2. 7e47402 Spelling fixes supplied by Rob W. W. Hooft. All these are fixes in either by Thomas Wouters · 25 years ago
3. 2850d18 Switch to sre for regular expression matching (the new mini-re module by Guido van Rossum · 25 years ago