ENH: Added a mark_as_advanced() wrapper function.

Modules/Findosg_functions.cmake

@@ -88,3 +88,13 @@ function(OSG_FIND_LIBRARY module library)
 
 
 endfunction(OSG_FIND_LIBRARY module library)
+
+#
+# OSG_MARK_AS_ADVANCED
+# Just a convenience function for calling MARK_AS_ADVANCED
+#
+function(OSG_MARK_AS_ADVANCED module)
+   mark_as_advanced(${module}_INCLUDE_DIR)
+   mark_as_advanced(${module}_LIBRARY)
+   mark_as_advanced(${module}_LIBRARY_DEBUG)
+endfunction()