Wired up timelines reset outline button.

app/assets/javascripts/angular/directives/timelines/timeline-toolbar-directive.js

@@ -53,6 +53,9 @@ angular.module('openproject.timelines.directives')
           scope.currentScaleIndex--;
         }
       };
+      scope.resetOutline = function(){
+        scope.timeline.expandTo(0);
+      }
 
       scope.$watch('currentScaleName', function(newScaleName, oldScaleName){
         if (newScaleName !== oldScaleName) {

public/templates/timelines/toolbar.html

@@ -31,7 +31,7 @@
   <div class="tl-toolbar-container" style="width: 1px; height: 20px; background-color: rgb(0, 0, 0);"></div>
 
   <div class="tl-toolbar-container">
-    <a href="javascript://" title="Reset Outline" class="icon tl-icon-outline"></a>
+    <a href="javascript://" title="Reset Outline" class="icon tl-icon-outline" ng-click="resetOutline()"></a>
   </div>
 
   <div class="tl-toolbar-container">