contrib/plan9/proto

releasenotes: add similarity check function to compare incoming notes

It is possible that the incoming note fragments have some similar content as the
existing release notes. In case of a bug fix, we match for issueNNNN in the
existing notes. For other general cases, it makes use of fuzzywuzzy library to get
a similarity score. If the score is above a certain threshold, we ignore the
fragment, otherwise add it. But the score might be misleading for small commit
messages. So, it uses similarity function only if the length of string (in words)
is above a certain value. The patch adds tests related to its usage. But it needs
improvement in the sense of combining incoming notes. We can use interactive mode
for adding notes. Maybe we can do this if similarity is under a certain range.

lib	- sys sys
	mercurial	- sys sys
		hgrc.d	- sys sys
			9diff.rc	- sys sys
			factotum.rc	- sys sys
rc	- sys sys
	bin	- sys sys
		9diff	- sys sys
		hg	- sys sys
sys	- sys sys
	lib	- sys sys
		python	- sys sys
			lib	- sys sys
				python2.5	- sys sys
					site-packages	- sys sys
						hgext	- sys sys
							+	- sys sys
						mercurial	- sys sys
							+	- sys sys
						mercurial-VERSION-py2.5.egg-info	- sys sys
	src	- sys sys
		cmd	- sys sys
			hg	- sys sys
				+	- sys sys