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
% file replaced with directory
adding a
% should fail - would corrupt dirstate
abort: file 'a' in dirstate clashes with 'a/a'
% directory replaced with file
adding a/a
% should fail - would corrupt dirstate
abort: directory 'a' already in dirstate
% directory replaced with file
adding b/c/d
% should fail - would corrupt dirstate
abort: directory 'b' already in dirstate