Added more information on option.

Author: robertosfield

CMakeLists.txt

@@ -90,7 +90,7 @@ if (VSG_SUPPORTS_Windowing)
     endif()
 endif()
 
-option(VSG_USE_dynamic_cast "Use dynamic_cast in vsg::Object::cast<T>(), 0 for off, 1 for enabled." OFF)
+option(VSG_USE_dynamic_cast "Use dynamic_cast in vsg::Object::cast<T>(), default is OFF and uses VSG native casting which provides 2-3x faster than using dynamic_cast<>." OFF)
 
 # this line needs to be after the call to setup_build_vars()
 configure_file("${VSG_SOURCE_DIR}/src/vsg/core/Version.h.in" "${VSG_VERSION_HEADER}")