Allow changing the 20s delay on Reverse DCC

[Riamus]

I would like to see an option to set your own delay on a file send when using Reverse DCC. Here are 2 reasons for that:

1) It is set so that it is 20s from the time you manually choose DCC before it pops up the send dialog box (easier to have it popup immediately).

2) When using fservs, people already typed /dccserver +sc on PORT if they are on the fserv... so no need to have a delay on downloading from an fserv.

The last one is obviously for people who use only fserv (cuz xdcc would probably need that delay to type it). Of course, since people see a message about why it didn't work, they can just try again if the timer is too low.

I'd just like to see an option for that so I don't have to edit the scripts to reduce the manual DCC to 0s and the Fserv dcc to 5s delay. Thanks.