Unused variable.
Properly implemented receive timeout for windows.

Changed interface of some functions to receive timeout in milliseconds,
instead of struct timeval.
RECVTIMEOUT is now unused.
Handle case of timeout set to 0, as block forever.
Guard against FD_SETSIZE limit for select()

Also document raising FD_SETSIZE for MinGW and some other
windows-specific hacks.
Remove trust which is now a flag in ConnectionFlags.