message: Include Span in Min / Max Duration labels
diff: @@ -118,7 +118,7 @@ export class JaegerToolbar extends React.Component<JaegerToolbarProps, JaegerToo
  <TagsControl tags={this.state.tags} onChange={e => this.setState({ tags: e.currentTarget.value })} />
  <FormGroup style={{ display: 'inline-flex' }}>
  <Col componentClass={Form.ControlLabel} style={{ marginTop: '4px' }}>
  - Min Duration
  + Min Span Duration
  </Col>
  <FormControl
  type="text"
  @@ -131,7 +131,7 @@ export class JaegerToolbar extends React.Component<JaegerToolbarProps, JaegerToo
  </FormGroup>
  <FormGroup style={{ display: 'inline-flex' }}>
  <Col componentClass={Form.ControlLabel} style={{ marginTop: '4px' }}>
  - Max Duration
  + Max Span Duration
  </Col>
  <FormControl
  type="text"
  