adds support for a portable db import/export format (closes: #1521112) the db-dump and db-restore cwctl commands are enhanced with a --format option (defaults to 'native'). If the format is 'portable', then the system database dump / restore is performed using pure SQL queries and the storage uses picked Python objects in a zip archive.

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
syntax: regexp
.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*