CPython migrated from CVS to Subversion, to Mercurial, and then to
Git. CVS and Subversion are not more used to develop CPython.
* platform module: drop support for sys.subversion. The
sys.subversion attribute has been removed in Python 3.3.
* Remove Misc/svnmap.txt
* Remove Tools/scripts/svneol.py
* Remove Tools/scripts/treesync.py
This is mostly to help history-digging, especially when
focussing on feature branches.
Note that not all changesets are in the main repository,
but they are all in the full history repository.