Add ability to send messages from server

The `foundation-flash-messages` package is currently client-only. Messages can only be added from the client side.

Yet sometimes the server might wish to push messages to the client as well. I modified the package to let both client and server send messages and have all of them show up on the client.

In addition I made the close button work in the alert box, and updated the tests for Meteor 0.8 and Blaze. The second test still fails, however.