Ensure every children of brick-deck is a brick-card

Enable brick-deck to use any element type, if it's not a brick-card it will automatically get wrapped by one 
In the test I had to use a polling strategy as in the MutationEvent the replacement is async, same for the create case, the element will not be available until after create.
Fixes #6

ps. this pr also fix a problem with gulp and karma, where gulp was overriding the karma configuration filenames, giving 404 errors in the html import, which made the test fail ad done was never called in the before all rule.