Use an absolute path for DATADIR
Use an absolute path for DATADIR

Without this, I get a seg fault whenever I run the binary from a
directory other than gummi/src.

closes #369

git-svn-id: b62a74e6a85b74e782ead772f54cba8e909798b9@1220 6e728def-ac18-4b39-bad8-e7d984b3b6fa

aitjcize/Gummi,aitjcize/Gummi,aitjcize/Gummi,aitjcize/Gummi