Sort of ancillary, but this URL should use https (the http URL is in fact hanging at the moment)
Fixes #68 by checking the git version and not using --count when git is less than 1.7.2
Alternate fix that I came up with immediately after the previous one.  This is better because it doesn't require running a separate process to check the git version every single time.  Instead it just assumes --count will work, but if it doesn't git returns error code 129, in which case we can then try a fallback.  That means slight slowdown for older git versions, but no penalty for newer git versions.  This also fixes the *original* issue that brought this up, which was that when an error occurred when running git the warning message didn't properly decode stderr :/
Slightly cleaner handling of I/O decoding
Add changelog entries for the fixes in this PR
Merge pull request #70 from embray/issue-68

Alternate fix for #68