Added observable._getValue().

An way for (internal) Methods to get the value with out beeing registered
by the Observer. For cases where you need the observable value but don't
want to get updated if it changes (In my case the update function of the options
data-query)

src/query/observable.js

@@ -65,6 +65,10 @@ define([
     observable._elementKeys = {};
     observable._elements = [];
 
+    observable._getValue = function () {
+      return getObservableValue(observable);
+    };
+
     if (blocks.isArray(initialValue)) {
       blocks.extend(observable, blocks.observable.fn.array);
       observable._indexes = [];