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
% initial svn import
Adding t/a
Committed revision 1.
% update svn repository
A t2/a
Checked out revision 1.
A b
Sending a
Adding b
Transmitting file data ..
Committed revision 2.
% convert to hg once
assuming destination trunk-hg
initializing destination trunk-hg repository
scanning source...
sorting...
converting...
1 init
0 changea
% update svn repository again
Sending a
Sending b
Transmitting file data ..
Committed revision 3.
% test incremental conversion
assuming destination trunk-hg
destination trunk-hg is a Mercurial repository
scanning source...
sorting...
converting...
0 changeb