Changed BusPacket format

Protocol requires to receive 2 bytes of length information for each packet and must be
terminated with a certain byte to ensure sync of sender and receiver.
Mhmm, simplified packet format once more.

The "lost" information should be handled in the payload / layer 2.
in development...
Added Hook definitions

Classes for hook types (pre, post, failed, route, connect, disconnect)
MasterHook that handles all calls to the hooks
Removed address from the Bus itself (will be handled by hooks)
Removed address field from BusPacket
Integrated hooks into Mbus

All hooks are now called on the masterhook instance.
Masterhook calls list of hooks
Fixed minor errors.

BusPacket destructor: fixed deletion of content (when nullptr)
Adapted disconnect routine of MBus

(cherry picked from commit c70911ef51c766f9dc385a2a4993544eed9fa123)
Changed protocol to string style

Size of packet now preceeds packet in 4 byte hexadecimal notation.
Added license file