Honour $XDG_DATA_HOME for &directory setting

'~/.local/share' is only the fallback location for data files, see http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html .

I'm sure there is a far cleaner way to implement this, but I figured a nasty looking fix is better than an issue with no attempt at a fix ;)

Thanks,

James

PS. Love the concept of this repo!