Update to 1.0.15:

Changes between version 1.0.13 and 1.0.14

Big improvements to side-by-side diff detection, thanks Peter Wu.  Additional
colordiffrc example colour scheme file to match 'git diff'.  Misc fixes thanks
to John Szakmeister, Matthew Wang.

Changes between 1.0.14 and 1.0.15

Missed gitdiff file from tarball, bumping version number for clarity.

(wiz)