Updated Vehicle to use transform as pure virtual, so Vehicle derived
classes can implement this value. Also added a transform(std::queue)
version so the threaded server and the controller thread can talk to
each other.

Updated therads to change dashee::Exit for a clean exit.

ServoDummy now memsets the buffer in its contructor, was looking at
memleaks on valgrind to try to eval this. Need to investigate further.
servod.cpp now has the main loop commented out, I just need to get a
controller class working before I am a 100% on removing the code