Added 'auto connect' checkbox to connect dialog. 

When the main window becomes active for the first time and auto connect is set to true, it will call connectToServer at that point.

![cockatrice_auto](https://cloud.githubusercontent.com/assets/812199/4066941/ee081440-2e28-11e4-9db5-ff05948a4cff.png)

Why not put the `tr`? It doens't break on adding new strings.