Removed registration for deprecated RPC interface

This old system was never committed to GIT,
but the registration survived ;-)
Separated parsing of RPC specification from dispatcher creation

The RPC specification file was parsed in the constructor of
RPCDispatcher, which is not possible on the client, since the campaign
to load is unknown, yet.
Support externaly supplied ScriptEngine in campaign::Manager

The script engine has to be created eraly on the client side, so
Manager should support "external" script engines.
Support automatic handler argSpec deduction thru AS reflection and rpc.tab

Compare the declaration of an AS RPC handler to the argument specification
from the rpc.tab. This ensures the supported arguments and their types
match throughout the whole game system.

In case the declaration mismatches, a graceful error message is thrown.
Correctly handle source client IDs on the server side

Use the client ID from the ClientSession when parsing packages
in the UdpConnection class. The ID is then used in the RPC system
to find the correct handler for incoming RPC packages.
Sync game state only to active clients
Store client activity in ClientSession property
Implemented stub client/server negotiation

On connection, a client has to send some information about itself to
the server, which in turn decides to accept or refuse the connection.

For testing purposes, a rather dumb implementation is presented using
the RPC system. It will connect any client, version numbers and the
campaign are hard-coded. The client name will be stored, though, but
it is not checked for duplicates.

A "correct" implementation should implement the RPC handlers in the
campaign::ServerLogic and campaign::ClientLogic classes.
Perform client negotiation in game client

As usual, the game client is a stub implementation, yet, using the
stub client negotiation. This is for testing and documenting the RPC
system for future use.
RPC and package transmission related debug output added to UdpConnection

Level-4 debug output added. A message will be printed whenever packages
are sent (sic) and when RPC messages timeout or are acknowledged.