Defines DCCP packets. It follows the definition of RFC 4340
Adds the dccp state structure
1) Renames DCCPControlInfo to DCCPCommand
2) Moves the DCCP packet definitions to a specific dir
3) Undone changes commited on tcpclientserver
Adds the definition of DCCP packets previously removed
Update DCCPCommand and DCCPSocket.{h,cc} properly.

Adds a new set of codes and methods. Currently, the DCCPSocket
is much more similar to the TCPSocket interface

TODO: the applications inside src/applications/dccpapp/* must be
updated to support the new codes and methods.
Defines the DCCP states for the Finite State Machine