Slider prop error fix (#743)

* Cast to float.

* Force gas price and limit inputs to be numbers.

common/components/GasSlider/components/AdvancedGas.tsx

@@ -19,6 +19,7 @@ export default class AdvancedGas extends React.Component<Props> {
           <label>{translate('OFFLINE_Step2_Label_3')} (gwei)</label>
           <input
             className="form-control"
+            type="number"
             value={this.props.gasPrice}
             onChange={this.handleGasPriceChange}
           />
@@ -28,6 +29,7 @@ export default class AdvancedGas extends React.Component<Props> {
           <label>{translate('OFFLINE_Step2_Label_4')}</label>
           <input
             className="form-control"
+            type="number"
             value={this.props.gasLimit}
             onChange={this.handleGasLimitChange}
           />

common/components/GasSlider/components/SimpleGas.tsx

@@ -26,7 +26,7 @@ export default class SimpleGas extends React.Component<Props> {
               onChange={this.handleSlider}
               min={gasPriceDefaults.gasPriceMinGwei}
               max={gasPriceDefaults.gasPriceMaxGwei}
-              value={gasPrice}
+              value={parseFloat(gasPrice)}
             />
             <div className="SimpleGas-slider-labels">
               <span>{translate('Cheap')}</span>