Added topic publish

This way all widgets that may care about the login event can listen without having to have a reference to the login widget.
Trying to make the sign in button show activity.

it seems when it takes a while the enter button doesn't switch the buttons state allowing for multiple posts to the sign in server. i think your disabled method was bugged but I didn't check if this fixes it really.
Merge pull request #20 from agrc/usage-improvements

Usage improvements