Update README with build instructions.
Update README with build instructions.

sidmutha/SDC,SDC-Developers/SDC,UplinkCoder/SDC,sidmutha/SDC,deadalnix/SDC,UplinkCoder/SDC,deadalnix/SDC,JohanEngelen/SDC,UplinkCoder/SDC,schancel/SDC,bpr/SDC,bpr/SDC,SDC-Developers/SDC,DmitryOlshansky/SDC,deadalnix/SDC,DmitryOlshansky/SDC,carlor/SDC,schancel/SDC,schancel/SDC,DmitryOlshansky/SDC,JohanEngelen/SDC,sidmutha/SDC,JohanEngelen/SDC,SDC-Developers/SDC,bpr/SDC