merge_test: Output results in TAP format
merge_test: Set up gitattributes to reduce useless merge conflicts
commitfest_branches: Support text/plain patches ending in .diff
commitfest_branches: Support bzip2-compressed patches
commitfest_branches: Factor out apply_patch

Add workaround for git-commit author name requirements.  Improve error
handling.
commitfest_branches: Add -q to git checkout