Merge sensitive logging - duplicates

With the addition of merge sensitive logs, it is possible that a user
may get multiple copies of the same log message, one for the original
change, and one or more that gets pulled in as the result of a merge.
For example
'svn log -g repo_root_url'
would return the log messages for any branches, and the results of any
merges between branches.

Returning duplicate messages seems redundant and wasteful. On the other
hand, if we eliminate the duplicates, how do we decide which ones
disappear, and which one stays? By keeping the duplicates in, we keep
consistency in the output and eliminate additional bookkeeping in the
implementation.

Based on that, I'm inclined to leave the duplicates in, and just tell
people that they'll get 'em if that's what the ask for.

Any objections?

-Hyrum