updated history and docs

HISTORY.md

@@ -26,8 +26,8 @@ http://visjs.org
 
 ### Graph3d
 
-- Implemented options `xValueLabel` and `yValueLabel` for custom labels along
-  the x and y axis. Thanks @fabriziofortino.
+- Implemented options `xValueLabel`, `yValueLabel` and `zValueLabel` for custom labels along
+  the x, y, z axis. Thanks @fabriziofortino.
 
 
 ## 2014-09-16, version 3.5.0

docs/graph3d.html

@@ -489,6 +489,14 @@ var options = {
   <td>none</td>
   <td>Step size for the grid on the z-axis.</td>
 </tr>
+<tr>
+  <td>zValueLabel</td>
+  <td>function</td>
+  <td>none</td>
+  <td>A function for custom formatting of the labels along the z-axis,
+    for example <code>function (z) {return (z * 100) + '%'}</code>.
+  </td>
+</tr>
 
 <tr>
   <td>xLabel</td>