Added .cc file for classes/structs that only provided by header
file. Defined non-POD classes' ctor, dtor in .cc file. Moved
implementation code in header file to .cc file for major
classes/strucsts.
Added --bt-lpd-interface option to specify the interface to use
for Local Peer Discovery. LpdMessageDispatcher object now has its
own socket. LpdMessageReceiver's socket is binded to multicast
address to only receive multicast packets.
* src/BtSetup.cc
* src/LpdMessageDispatcher.cc
* src/LpdMessageDispatcher.h
* src/LpdMessageReceiver.cc
* src/LpdMessageReceiver.h
* src/LpdReceiveMessageCommand.cc
* src/LpdReceiveMessageCommand.h
* src/OptionHandlerFactory.cc
* src/SocketCore.cc
* src/SocketCore.h
* src/prefs.cc
* src/prefs.h
* src/usage_text.h
* test/LpdMessageDispatcherTest.cc
* test/LpdMessageReceiverTest.cc