Fixed a failing test (CHECK_EQUAL -> BYTES_EQUAL)

I wonder why this overload does work on Fedora but not on ArchLinux
Switched the $(CXX) of test/Makefile to clang BUILD IS STILL FAILING DUE TO LINKER ERROR
Make clean does now run the clean target on all Makefiles in the subdirectories again

Just to be sure everything is properly cleaned
Fixed issue in the linking process (missing libm)

The omnet++ part and the tests did not compile well because it seems
like clang does not add the libm (math library) to the linker flags by default
Merge branch 'clangInTests' into develop
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 method stubs for handling route discovery timer
added stub for class RouteDiscoveryTimer
removed RouteDiscoveryTimer
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