interhg: allow more flexible pattern specification (fixes 2/3 of issue699)
- something else than "pat" followed by a number can be used as key
- something else than "/" can be used as delimiter
- "ilmsux" flags (e.g. "i" for case insensitive) can be used
abort: index 00changelog.i unknown format 2!
abort: requirement 'indoor-pool' not supported!