style(app.js, pickers): update pickers containers, update App.js styles

Remove static 500px height for overlay and drop-pane components, keep static height for inline
picker, add styles to example pickers

Author: Jakub Peksa

example/src/App.js

@@ -39,7 +39,7 @@ const App = () => {
         </button>
       </div>
       <div>
-        {isPickerDropPaneVisible && <PickerDropPane apikey='YOUR_APIKEY'/>}
+        {isPickerDropPaneVisible && <PickerDropPane apikey='YOUR_APIKEY'><div style={{height: '800px'}}/></PickerDropPane>}
         {isPickerInlineVisible && <PickerInline apikey='YOUR_APIKEY'/>}
         {isPickerOverlayVisible && <PickerOverlay apikey='YOUR_APIKEY'/>}
       </div>

src/picker/picker-drop-pane.jsx

@@ -26,7 +26,7 @@ const PickerDropPane = ({
     if (children) {
       return React.cloneElement(children, { id: containerId });
     }
-    return <div style={{ height: '500px' }} id={containerId} />;
+    return <div id={containerId} />;
   };
   return render();
 };

src/picker/picker-overlay.jsx

@@ -23,7 +23,7 @@ const PickerOverlay = ({
     if (children) {
       return React.cloneElement(children, { id: containerId });
     }
-    return <div style={{ height: '500px' }} id={containerId} />;
+    return <div id={containerId} />;
   };
   return render();
 };