Added dynamic network switching in test_broadcast.cpp. PRISM will attempt to connect to the configured wifi ssid, and if it fails after so many attempts, it will revert to AP mode and host its own network. Added a command to be able to tell PRISM to connect to a specific ssid. Added scripts to help switching between client wifi mode and ap wifi mode. Modified Network.h and Network.cpp to retrieve the broadcast address for any given network interface.