Merge branch 'maint'

* maint:
Fix git-svn to handle svn not reporting the md5sum of a file, and test.
Fix mishandling of $Id$ expanded in the repository copy in convert.c
More echo "$user_message" fixes.
Add tests for the last two fixes.
git-commit: use printf '%s\n' instead of echo on user-supplied strings
git-am: use printf instead of echo on user-supplied strings
Documentation: Add definition of "evil merge" to GIT Glossary
Replace the last 'dircache's by 'index'
Documentation: Clean up links in GIT Glossary

diff --cc diff.c
Simple merge

diff --cc git-merge.sh
Simple merge