#9607: Add tests for the keyword module.

Based on the testing ideas in a patch written by Greg Malcolm.
#9607: restore keywords.kwlist after testing it.
Make license notices more consistent and remove old changelog.
Also remove unused macro.
Update ET documentation reprhasing the mention of the new IncrementalParser in
the doc for iterparse.
Fix trailing whitespace
Remove useless #define and #ifdefs
Add some documentation for IncrementalParesr
Remove superfluous try/except
Issue #16694: Add a pure Python implementation of the operator module.
Patch by Zachary Ware.
#17409: Document RLIM_INFINITY and use it to clarify the setrlimit docs.
Merge #17409: Document RLIM_INFINITY and use it to clarify the setrlimit docs.
Isuse #17720: Fix APPENDS handling in the Python implementation of Unpickler
to correctly process the opcode when it is used on non-list objects.
Merge 3.3
Issue #17801: fix shebang line of gprof2html.py
Issue #17801: fix shebang line of gprof2html.py