When run_tests.py is run from a Subversion copy (and probably CVS,
Mercurial as well), the standard template is copied (lots of times),
preserving all file attributes (this might be a problem specific to
Windows / OSes which use FAT-style file attributes: On Windows, readonly
and system attributes prevent file deletion), causing errors when the
temporary tree is to be deleted.

This patch makes the roundup.init.copytree function skip CVS, Subversion
and Mercurial special directories: No copying of special files, no
attribute problems when cleaning up.

(sorry, I can't use Keywords here; no read access! Would a "Testing"
component be useful?)