Added a render order sort to the list of Cameras being tested by the *Viewer::generatePointerData(..) method to ensure that the highest Camera gets focus.

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/branches/OpenSceneGraph-3.2@14311 16af8721-9629-0410-8352-f15c8da7e697

src/osg/ApplicationUsage.cpp

@@ -15,6 +15,7 @@
 #include <string.h>
 
 #include <osg/ApplicationUsage>
+#include <osg/Object>
 #include <osg/Math>
 #include <osg/ref_ptr>
 
@@ -33,6 +34,8 @@ ApplicationUsage* ApplicationUsage::instance()
     return s_applicationUsage.get();
 }
 
+OSG_INIT_SINGLETON_PROXY(ApplicationUsageSingletonProxy, ApplicationUsage::instance())
+
 void ApplicationUsage::addUsageExplanation(Type type,const std::string& option,const std::string& explanation)
 {
     switch(type)
@@ -69,7 +72,7 @@ void ApplicationUsage::addKeyboardMouseBinding(const std::string& prefix, int ke
     {
         std::ostringstream ostr;
         ostr<<prefix;
-        
+
         if (key==' ')
         {
             ostr<<"Space";