Fixed controller prototype for update.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@1847 f9c3cf11-9bcb-44bc-f272-b75c42450872

libraries/AP_Controller/AP_Controller.h

@@ -76,7 +76,7 @@ public:
         }
         _blocks.push_back(block);
     }
-    virtual void update(const double dt)
+    virtual void update(const float & dt)
     {
         for (int i=0;i<_blocks.getSize();i++)
         {