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()
* Added whatis command to pdb.py
* new module GET.py (GL definitions from <gl/get.h>)
* rect.py: is_empty takes a rect as argument, not two points.
* Added tests for builtin round() [XXX not yet complete!]