1.7.0

• Add support for sandbox option to providers (defaults to false). When sandbox is set to true, no transaction is actually transmitted to the blockchain, but rather a check whether the transaction would be successful is performed (via estimateGas).
• Add support for gasPriceMultiplier to providers (defaults to 1.1). This option sets a multiplier which is applied when creating a mutation. Calculation of gas price is made by first calling eth_gasPrice and then multiplying the result with the gasPriceMultiplier. This way, we can dynamically adjust the gas price for optimal results. You can still manually set the gas price per specific mutation.