Handle case with no commits between tags.
tree07fa995caff13e794d996114887822e75990d52d
-rw-r--r-- 73 arrow-down.gif
-rw-r--r-- 71 arrow-none.gif
-rw-r--r-- 73 arrow-up.gif
drwxr-xr-x - doc
-rwxr-xr-x 29740 gitstats
-rw-r--r-- 1258 gitstats.css
-rw-r--r-- 9553 sortable.js