Fix open bugs, latest packaging standards, lintian-issues

Dear Alastair,

since igaelic came up today as a candidate for the Bug of the Day I've spent some time into this package. I will tag the single bugs as patch (with links to the actual commit) and leave you the decision to merge everything or cherry-pick. I also added Vcs fields to the location where I found your repository. You might want to move it to Debian team and if you do so please adjust the Vcs fields accordingly.

I admit I had trouble to find some upstream URL / Homepage. I guess you are also upstream but I have no idea how you are doing the versioning. Please clarify the situation in d/copyright to let people know where the code comes from. BTW, this is the reason why I did not migrated to DEP5 copyright.

I'm also a bit unsure about commit 40d0b4b7. With the empty Description fields in d/wgaelic.po-master.templates lintian throws an error. If you think the Description should remain empty please revert this and use lintian-overrides instead.

Hope this helps, Andreas.