Moved many things to Login.js

Resolves #1112.

http://jenkins.buttonweavers.com:8080/job/buttonmen-AdmiralJota/399/

In addition to the tests for whether or not the player is logged in, I also moved a bunch of common code from the ```Foo.showFooPage()``` and ```Foo.arrangePage()``` methods in the individual files to ```Login.arrangeHeader()``` and ```Login.arrangePage()``` so that it can be shared. 

Most pages don't even need their own ```arrangePage()``` method anymore (so I took them out, just having them call ```Login.arrangePage()``` instead), and there are several pages where we should probably merge ```Foo.showFooPage()``` with ```Foo.getFoo()``` at some point, since there's so little there now.
In the Game.js case, i'm not crazy about the fact that there are three arguments to `Login.arrangePage()`, and each of the dozen or so locations from which that's invoked have to track all of them.  Is there any sense in retaining `Game.arrangePage()` and just having it be a one-liner which invokes `Login.arrangePage()` with the right arguments?

Again, not a dealbreaker at all, just asking the question.