googlefontdirectory: new package

Note that the Google code project does not provide an archive containing
just the font files. This package uses the third party archive provided at

  http://joemaller.com/1856/download-google-fonts/

Further information is available at the following URL.

  http://code.google.com/p/googlefontdirectory/issues/detail?id=2



[Peter: drop version, fix install and simplify uninstall]
Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>