Started documenting router using doxygen
Documented routing_table.c for doxygen
Documented payload_handlers, auth_status
Documented dispatch code with doxygen
Documented heartbeat.h, heartbeat.c using doxygen
Documented payloads.h using doxygen
Documented communication source files for router

Using doxygen
Added documentation for sg_tcp.c and main.c
Merge branch 'testing'