Use cached share list

[Cezariusz]

I have a lot of files and dirs shared, so it takes some time for the DC++ to startup because of refreshing share list.
What I'd like to see is DC++ loading MyList.bz2 if it existed, and then spawning a thread to refresh the list. It would make DC++ startup much faster and share list would be soon refreshed in the background.

[mo]

makes sense to me