Structure changes and some name changes

The project now able to run on the Raspberry Pi
1. Add Makefile, currently make an executable, need to change to make a shared library
2. Divide the topologies to ring_topo and d_topo, d_topo remain untested
3. DNS now available, raspberry pi is in the zone ".yang"
   zephyr.yang pi.yang lan.zephyr.yang   10.11.18.60
   wifi.zephyr.yang				     10.11.18.61