Add 'git subtree merge' and 'git subtree pull'.
tree96bcc32545dde0cc3e2afb0f1e2a497793aed9e9
-rw-r--r-- 3 .gitignore
lrwxrwxrwx 14 git-subtree -> git-subtree.sh
-rwxr-xr-x 7840 git-subtree.sh
-rw-r--r-- 23 shellopts.sh
-rwxr-xr-x 1926 test.sh