message: KIALI-GH-1211 Improve layout popups
  * KIALI-GH-1211 Improve layout tooltips
  Also, add tooltips for zoom options
diff: import * as React from 'react';
  -import { ButtonGroup, Button, Icon } from 'patternfly-react';
  +import { ButtonGroup, Button, Icon, OverlayTrigger, Tooltip } from 'patternfly-react';
  import { style } from 'typestyle';
  import { connect } from 'react-redux';
  import { bindActionCreators } from 'redux';
  @@ -64,49 +64,69 @@ export class CytoscapeToolbar extends React.PureComponent<CytoscapeToolbarProps>
  return (
  <div className={cytoscapeToolbarStyle}>
  <ButtonGroup>
  + <OverlayTrigger key={'ot_ct_zi'} placement="top" overlay={<Tooltip id={'tt_ct_zi'}>Zoom in</Tooltip>}>
  <Button onClick={this.zoomIn}>
  <Icon type="fa" name="plus" />
  </Button>
  -
  + </OverlayTrigger>
  + <OverlayTrigger key={'ot_ct_zo'} placement="top" overlay={<Tooltip id={'tt_ct_zo'}>Zoom out</Tooltip>}>
  <Button onClick={this.zoomOut}>
  <Icon type="fa" name="minus" />
  </Button>
  + </OverlayTrigger>
  </ButtonGroup>
  + <OverlayTrigger key={'ot_ct_ztf'} placement="top" overlay={<Tooltip id={'tt_ct_ztf'}>Zoom to fit</Tooltip>}>
  <Button onClick={this.fit} className={cytoscapeToolbarPadStyle}>
  <div className="glyphicon glyphicon-fullscreen" />
  </Button>
  + </OverlayTrigger>
  <ButtonGroup id="toolbar_layout_group" className={cytoscapeToolbarPadStyle}>
  + <OverlayTrigger
  + key={'ot_ct_l0'}
  + placement="top"
  + overlay={<Tooltip id={'tt_ct_l0'}>Layout default ({DagreGraph.getLayout().name})</Tooltip>}
  + >
  <Button
  onClick={() => {
  this.props.setLayout(DagreGraph.getLayout());
  }}
  - title={DagreGraph.getLayout().name}
  active={this.props.layout.name === DagreGraph.getLayout().name}
  >
  <div className="fa pficon-infrastructure fa-rotate-270" />
  </Button>
  + </OverlayTrigger>
  + <OverlayTrigger
  + key={'ot_ct_l1'}
  + placement="top"
  + overlay={<Tooltip id={'tt_ct_l1'}>Layout 1 ({CoseGraph.getLayout().name})</Tooltip>}
  + >
  <Button
  onClick={() => {
  this.props.setLayout(CoseGraph.getLayout());
  }}
  - title={CoseGraph.getLayout().name}
  active={this.props.layout.name === CoseGraph.getLayout().name}
  >
  <div className="fa pficon-topology" /> 1
  </Button>
  + </OverlayTrigger>
  + <OverlayTrigger
  + key={'ot_ct_l2'}
  + placement="top"
  + overlay={<Tooltip id={'tt_ct_l2'}>Layout 2 ({ColaGraph.getLayout().name})</Tooltip>}
  + >
  <Button
  onClick={() => {
  this.props.setLayout(ColaGraph.getLayout());
  }}
  - title={ColaGraph.getLayout().name}
  active={this.props.layout.name === ColaGraph.getLayout().name}
  >
  <div className="fa pficon-topology" /> 2
  </Button>
  + </OverlayTrigger>
  </ButtonGroup>
  <Button
  