Assegnate 5 su 5 stelle

It seems user twang817 fixed this by editing file gmServiceGmail.js.

See yourself:
https://github.com/twang817/firefox-gmail-manager-ng/commit/949259272590c0034f9268141eb4fed985051c4b

But he did not create a new release.
0.6.5.4 would be the new version I think.

Anyone up to it?