toJsonHex with an empty byte array produces "0x" which does not work in the remix IDE

[tbocek]

{"jsonrpc":"2.0","id":63,"result":{"hash":"0x4f2a5...","nonce":"0x00", "blockHash":"0x57698...","blockNumber":"0x2","transactionIndex":"0x0", "from":"0x5c5a...","to":"0x","gas":"0x012118","gasPrice":"0x0ba43b7400", "value":"0x","input":"0x608060405260..."}}

The problem with "to":"0x" and "value":"0x" is that the remix IDE cannot convert those numbers and throws the following exception: "Error: new BigNumber() not a base 16 number"

This fix checks if the byte array or the resulting string is empty and if it is the case it returns 0x0. This fixes the issue with the remix IDE

[tbocek]

This breaks other thing, according to https://github.com/ethereum/wiki/wiki/JavaScript-API#web3ethgettransactionreceipt, value must be a BigNumber, I'll create a new pull request with only this fix