#74 Win32: Implement optional systray icon

[Dossy Shiobara]

On Win32, allow enabling of a systray icon from the
config .tcl script.

The systray icon might have several options: "stats" -
display some basic statistics (number of connections,
max connections, etc.); "control port" - open a simple
window which simulates the control port, taking input
and evaluating it and displaying the results; etc.