New install yields error rendering *head (raw view) and CoffeeScript::SyntaxError+discussion

I could reproduce this. It seems to be a problem with the uglifier gem. It is locked in card.gemspec to ~2.5. Uglifier 2.7.2 fails (sometimes) to compress the javascript of the "script: jquery helper" card. With 3.0.0 the problem was gone. I made a pull request with a card.gemspec update to solve this. I guess we need a new point release.

Re db/seed: The seed data is a git submodule so the proper way to get the seed data is to run `git submodule update --init`. Is the core developer setup documented somewhere? If so this should be mentioned there.