Adding "--no-merges" to git log to fix _history

Merge commits do not generate a change line
("1 file changed, 61 insertions(+), 67 deletions(-)"
as seen in --shortstat). We'll skip those for our
purposes.

Without this change, merges in the history of
a file break the _history view.
Merge pull request #11 from handyman5/bugfix/git_history_merges

Adding "--no-merges" to git log to fix _history