Moved address name query dialog to constructor

The dialog that asks for the name of the address popped up when the
EventProcessor was told to send packets. The dialog now pops up on the
construction of EventProcessor which happens before the game begins.
This place was more fitting.
Adds a network listener to receive input packets

Adds a network listener which listeners for a Datagram on socket 1729.
When a datagram is received it is used to construct an InputEvent which
is added to the EventQueue to be processed.