Improve README.md
Improve README.md

Change-Id: Iac2cd5a0859b5995eff7741e1e1d234cc2fad3ec

opennetworkinglab/onos,gkatsikas/onos,kuujo/onos,kuujo/onos,oplinkoms/onos,oplinkoms/onos,kuujo/onos,oplinkoms/onos,gkatsikas/onos,gkatsikas/onos,kuujo/onos,oplinkoms/onos,kuujo/onos,oplinkoms/onos,opennetworkinglab/onos,kuujo/onos,opennetworkinglab/onos,opennetworkinglab/onos,gkatsikas/onos,oplinkoms/onos,opennetworkinglab/onos,kuujo/onos,gkatsikas/onos,opennetworkinglab/onos,gkatsikas/onos,oplinkoms/onos