tests/test-issue619.out

color: add --color switch

--color works like GNU grep --color. --color=auto only colorizes output
for non-dumb terminals that are TTYs.

adding a
marked working directory as branch b
adding b
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
fast-forward
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
bogus fast-forward should fail
abort: can't merge with ancestor
done