starting to use gitinfo
gitinfo is working!
checking that the hash changes in the document
checking again
now gitinfo is really working (permissions issue)

if you encounter this again, chmod +x ./.git/hooks/post-* (when you
copy post-xxx-sample.txt from the gitinfo source package, you don't get
the right permissions)
changed .gitignore to reflect the fact that gitHeadInfo.gin changes post-commit
didn't edit .gitignore properly last time
.gitignore is now working