-Add reference-counted object pool scheme to the Packet class.

git-svn-id: http://odamex.net/svn/root/branches/net3-base@4595 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Fix a few bugs with Packet::readPacketData and writePacketData.
-Change the packet sending and receiving functions in the Connection and NetInterface classes to use Packets instead of BitStreams.

git-svn-id: http://odamex.net/svn/root/branches/net3-base@4596 b0bcef46-2027-0410-bd56-ab726e9a1d04