Added diagram source to docs
Added diagram source to docs

mrquincle/nRF51-ble-bcast-mesh,mrquincle/nRF51-ble-bcast-mesh,ihassin/nRF51-ble-bcast-mesh,ihassin/nRF51-ble-bcast-mesh,mrquincle/nRF51-ble-bcast-mesh,mrquincle/nRF51-ble-bcast-mesh