negative start indices starting from the right.
* ftplib.py: debug() -> set_debuglevel(); change demo to use __init__().
* os.py: added execl, execlp, and execvp.
* lambda.py: removed (now that we have built-in map, reduce, bagof, lambda)
* test_b{1,2}.py, testall.out: added tests for bagof, lambda, map, reduce
* commands.py: use os, not posix
* test_grammar.py: make it easy to disable non-portable int overflow tests
* dis.py: don't abuse range()
* sndhdr.py: renamed to whatsound.py; use new aifc module for AIFF/AIFC
* ftplib.py: added close() (closes without sending QUIT command)
* aifc.py: documented close()
* Several modules: change "class C(): ..." to "class C: ...".
* flp.py: support for frozen forms.
* Added string.find() which is like index but returns -1 if not found
Guido van Rossum