Revert file[s] by filename pattern

It would be nice if "revert" could take a pattern of files to revert, rather than a list of names. This is particularly useful when the intent of the revert is to bring back a group of deleted files. A pipeline like "bzr ls | grep | xargs bzr revert" can accomplish much the same, but a "bzr revert --matching=$REGEXP" is much handier to type.

One use case: A set of files are extensively modified outside the VCS workflow (e.g., by other people). Files are added and removed without notification. Bringing in changes can be done most easily by 'rm -rf'ing the working tree files, copying in the current live files, add'ing new files, rm'ing (or allowing commit to auto-rm) the defunct files, and committing. However, various files (e.g., installation scripts or Makefiles) won't be present in that 'live' copy, but are still wanted in the repo. Thus, a command flow like: "rm -rf * ; cp -Rp $LIVELOC . ; bzr revert --matching='Makefile.*' ; (other stuff then commit)" could be used.