[repo transaction] fix rollback behaviour as discussed on the mailing-list: instead of rollbacking automatically on Unauthorized/ValidationError, mark the transaction as uncommitable and disallow commiting

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$