message: chart_with_upwards_trend: Ajoute le suivi des bulles d'aide
diff: @@ -6,6 +6,7 @@ import {connect} from 'react-redux'
  import {EXPLAIN_VARIABLE} from '../../actions'
  import {rules, findRuleByDottedName} from 'Engine/rules'
  +import ReactPiwik from 'react-piwik';
  @connect(state => ({explained: state.explainedVariable}), dispatch => ({
  explain: variableName => dispatch({type: EXPLAIN_VARIABLE, variableName})
  @@ -40,7 +41,12 @@ export default class Explicable extends React.Component {
  {ruleLabel}
  <span
  className="icon"
  - onClick={e => {e.preventDefault(); e.stopPropagation(); explain(dottedName)}}>
  + onClick={e => {
  + ReactPiwik.push(['trackEvent', 'help', dottedName]);
  + e.preventDefault();
  + e.stopPropagation();
  + explain(dottedName)
  + }}>
  <i className="fa fa-info" aria-hidden="true"></i>
  </span>
  </span>
  