remove null messages so that creation and verification proposal signatures match
remove null messages so that creation and verification proposal signatures match

isocolsky/bitcore-wallet-client,tanojaja/bitcore-wallet-client,MonetaryUnit/bitcore-wallet-client,bitjson/bitcore,bitpay/bitcore,JDonadio/bitcore-wallet-client,bitpay/bitcore,troggy/bitcore-wallet-client,bitpay/bitcore-wallet-client,martindale/bitcore,martindale/bitcore,bitpay/bitcore,philosodad/bitcore-wallet-client,bitjson/bitcore,studio666/bitcore-wallet-client,javierbitpay/bitcore-wallet-client,solderzzc/bitcore-wallet-client,nohea/alohacore-wallet-client,martindale/bitcore,kaibakker/bitcore-wallet-client,martindale/bitcore,bankonme/bitcore-wallet-client,bitjson/bitcore,dabura667/bitcore-wallet-client,matiu/bitcore-wallet-client,bitpay/bitcore,bitjson/bitcore