#88 Option for lmerge -f to ignore existing files.

[Jeff Kelley]

If you're using lmerge -f to merge a new transcript into an existing transcript, e.g. "lmerge -f Foo-1.1.T Foo.T," existing files in the file/Foo.T/ folder can cause a "file exists" error if the file isn't in the old transcript. If, for instance, you remove a line from a transcript and then use lmerge -f to merge a new transcript in that contains the file, it will try to link the file but fail because the file exists. I'd like an option for lmerge to delete the old file and link the new one to avoid doing this manually for large transcripts.