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)

Can you flip the condition blocks here?

Also, `if` blocks should get brace on the same line, see the style guide here: https://github.com/Daenyth/Cockatrice/blob/master/CONTRIBUTING.md#braces