lint fixes

src/components/Card.jsx

@@ -172,7 +172,7 @@ class Card extends React.Component {
         className={`event-card ${isSelected ? 'selected' : ''}`}
         id={`event-card-${idx}`}
         ref={this.props.innerRef}
-	      onClick={(e) => { this.props.onClick(idx) }} 
+        onClick={(e) => { this.props.onClick(idx) }}
       >
         {this.renderMain()}
         {this.state.isOpen ? this.renderExtra() : null}

src/components/CardStack.jsx

@@ -64,7 +64,7 @@ class CardStack extends React.Component {
       this.refs[idx] = thisRef
       return (<Card
         event={event}
-	      idx={idx}
+        idx={idx}
         ref={thisRef}
         sourceError={this.props.sourceError}
         language={this.props.language}