Renamed the class ARA to OMNeTARA.

This was necessary because there were name conflicts with the surrounding
namespace which was also called ARA. This was a bad idea anyway but now everything is fine
Separated the methods from members in the AbstractARAClient (better overview)
Introduced the AbstractNetworkInterface class
The NetworkInterfaceMock does now directly inherit from ReliableNetworkInterface
Current state of development (NOT building)
Added the test j4 eclipse build target (build with 4 cores)
Added a standard implementation of broadcast in the AbstractNetworkInterface
The NetworkInterface implementations are now responsible for deleting the packets when they have processed them.
Wrote the first tests for the ReliableNetworkInterface.

Complete acknowledgment logic is not completely implemented yet
Implemented much of the logic of ReliableNetworkInterface.

A big part is still missing: the ack timers and packet retransmission.
Implemented a Framework for the handling of abstract timers.

This does also implement most of the ReliableNetworkInterface
functionality
I'm sorry this is another huge commit :/
Renamed the TimeFactory to Clock
The RoutingTable does now use the static Environment class to retrieve a Clock instance

The constructors are now clean again :=)
The acknowledgment timers are now interrupted when an ack has been received
Fixed Bug in ReliableNetworkInterface: interfaces waited for acknowledgement of acks
Fixed segfault that occured if the environment clock had been changed after RoutingTable constructor
The Environment is now set within its own submodule (prevent mulitple initialization)

Howto handle singleton classes:
http://www.omnetpp.org/pmwiki/index.php?n=Main.CollectingGlobalStatistics
Fixed the OMNeTTimer implementation
Removed the include/omnetpp folder from the standard include folders.

This is neseccary for an effective use of the namespace
If I want to have 2 classes with the same name (and filename) in
separate folders.
Merge branch 'packetAcks' into develop

Please note that the Timer API is not yet implemented for OMNeT++

Conflicts:
	include/omnetpp/OMNeTARA.h
	omnetpp/OMNeTARA.cpp
	src/core/AbstractARAClient.cpp