Add stop command to rpcserver.
Add stop command to rpcserver.

FactomProject/btcd,soapboxsys/ombfullnode,Stash-Crypto/btcd,davecgh/btcd,cqswxj2013/btcd,btcsuite/btcd,jcmincke/dcrd,wallclockbuilder/btcd,cjepson/btcd,Cleawing/btcd,mathiasrw/btcd,ppcsuite/ppcd,dan-da/btcd,1d4Nf6/btcd,BitGo/prova,danoctavian/btcd,ppcsuite/ppcd-old,tb00/btcd,CryptocurrencyCabal/htcd,jcmincke/dcrd,Cleawing/btcd,FactomProject/btcd,aakselrod/btcd,Evil-Coin/Evil,1d4Nf6/btcd,jrick/dcrd,Evil-Coin/Evil,davecgh/btcd,wallclockbuilder/btcd,pkothbauer/btcd,qchain/btcd,glv2/ppcd,danoctavian/btcd,decred/dcrd,Roasbeef/btcd,Dirbaio/btcd,runeaune/btcd,hectorj/btcd,ppcsuite/ppcd,CryptocurrencyCabal/htcd,stevenroose/btcd,glv2/ppcd,Stash-Crypto/btcd,Dirbaio/btcd,stevenroose/btcd,BitGo/prova,dajohi/btcd,ppcsuite/ppcd-old,jcmincke/dcrd,dajohi/btcd,btcsuitereleases/btcd,cqswxj2013/btcd,jimmysong/btcd,dajohi/btcd,aakselrod/btcd,ltcsuite/ltcd,btcsuite/btcd,decred/dcrd,soapboxsys/ombfullnode,Roasbeef/btcd,dan-da/btcd,toddfries/btcd,pkothbauer/btcd,runeaune/btcd,jrick/btcd,sysbot/btcd,DanielKrawisz/btcd,jrick/dcrd,qchain/btcd,mathiasrw/btcd,DanielKrawisz/btcd,ltcsuite/ltcd,jongillham/btcd,jongillham/btcd,Dirbaio/btcd,cjepson/btcd,adiabat/btcd,hectorj/btcd,tb00/btcd,jimmysong/btcd,jrick/btcd,btcsuitereleases/btcd,adiabat/btcd,toddfries/btcd,jrick/btcd,sysbot/btcd