#124 Add an optional type parameter for modem option in [serial]

[CTxCB]

I'm wondering whether it'd be possible to add an optional type parameter to the modem in the serial section? Currently the modem broadcasts as TCP, which is fine if the program is broadcasting TCP through the modem, but what if they're broadcasting UDP or another type? Although it'd still default to TCP, there should be options for type:TCP, type:UDP, type:MODEM (for contacting another modem if the computer is attached to a phone line), or type:RAW (a passthrough, passes exactly as received) with them being case insensitive.