Add createencryptedwallet extension support.
Add createencryptedwallet extension support.

jrick/btcd,aakselrod/btcrpcclient,btcsuite/btcd,btcsuite/btcd,wallclockbuilder/btcd,tb00/btcd,FactomProject/btcrpcclient,jrick/dcrd,btcsuite/btcrpcclient,runeaune/btcrpcclient,ppcsuite/ppcd,jrick/btcrpcclient,decred/dcrd,FactomProject/btcrpcclient,Roasbeef/btcd,decred/dcrd,davecgh/btcd,btcsuite/btcrpcclient,jrick/btcd,ltcsuite/ltcd,ppcsuite/btcrpcclient,davecgh/btcrpcclient,jrick/btcrpcclient,ltcsuite/ltcd,Roasbeef/btcd,dajohi/btcd,dajohi/btcd,aakselrod/btcd,tb00/btcd,ppcsuite/ppcd,Stash-Crypto/btcd,davecgh/btcd,runeaune/btcrpcclient,aakselrod/btcd,wallclockbuilder/btcrpcclient,ppcsuite/btcrpcclient,jrick/dcrd,Stash-Crypto/btcd,wallclockbuilder/btcrpcclient,wallclockbuilder/btcd,dajohi/btcd,jrick/btcd,aakselrod/btcrpcclient