update to datastore 2.0.6

Author: graemerocher

build.gradle

@@ -28,7 +28,7 @@ ext {
     commonsCollectionsVersion = "3.2.1"
     commonsIOVersion = "2.1"
     commonsLangVersion = "2.6"
-    datastoreVersion = "2.0.5.RELEASE"
+    datastoreVersion = "2.0.6.RELEASE"
     gantVersion = "1.9.6"
     gdocEngineVersion = "1.0.1"
     groovyVersion = "2.1.9"