Updates to the latest {diff,merge}tool series
From: David Aguilar <hidden>
Date: 2016-06-15 22:46:34
Here they are.
07/14: Updated usage synopsis
09/14: Updated diff.tool config.txt documentation
10/14: The original broke the test suite on Mac OS...
Testing {diff,merge}tool.<tool>.path is tricky.
11/14: This depends on 07/14, so the rebase requires a resend
14/14: Reworked logic as discussed.