[repo api] deprecates source.extid2eid, only the system source should implement it, and one should directly use the repo api instead of this confusing and error-prone short-cut. Deprecates eid2ext as well for consistency.

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