Replaced old inactive sockets cleanup with more simple, based on closesocket().

Changed overflow queues on gateway to use internal memory instead of IPC chunks.
Merge branch 'develop' of https://github.com/Starcounter/Starcounter into develop
Fixed socket disconnect operations.
Merge branch 'develop' of https://github.com/Starcounter/Starcounter into develop
Fixed some chunk leakage bugs.
Added a check for null sd.