Add clickable coordinates in chat

Coordinates that are input during chat are now clickable. They will center a user over the hex as well as select that hex and highlight it.
If you want to see it not select the castle/village then in game.js lines 107 and 108 change "subs.subscribe" to "Meteor.subscribe" then it will be easy to make happen.

subs is for https://github.com/meteorhacks/subs-manager which caches the subscription.