add checks to getBalance
add checks to getBalance

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