Increase LINK_TABLE_OUT_SIZE from 101 to 4001 like LINK_TABLE_IN_SIZE

Increase LINK_TABLE_OUT_SIZE from 101 to 4001 like LINK_TABLE_IN_SIZE
to reduce performance degradation under heavy outgoing scan/flood.
Scalability is now much more important then several kilobytes of RAM.

Remove unneded TCP-specific expiration handeling. Before this connected
TCP sessions could never expire. Now connected TCP sessions will expire
after 24hours of inactivity.

Simplify HouseKeeping() to avoid several mul/div-s per packet. Taking into
account increased LINK_TABLE_OUT_SIZE, precision is still much more then
required.