Update SUMMARY.md

Author: lefticus

SUMMARY.md

@@ -1,12 +1,13 @@
- * [Preface](01-Preface.md)
- * [Use the Tools Available](02-Use_the_Tools_Available.md)
- * [Style](03-Style.md)
- * [Considering Safety](04-Considering_Safety.md)
- * [Considering Portability](05-Considering_Portability.md)
- * [Considering Threadability](06-Considering_Threadability.md)
- * [Considering Performance](07-Considering_Performance.md)
- * [Enable Scripting](08-Enable_Scripting.md)
- * [Further Reading](09-Further_Reading.md)
- * [Final Thoughts](10-Final_Thoughts.md)
+# Summary
 
+* [Preface](01-Preface.md)
+* [Use the Tools Available](02-Use_the_Tools_Available.md)
+* [Style](03-Style.md)
+* [Considering Safety](04-Considering_Safety.md)
+* [Considering Portability](05-Considering_Portability.md)
+* [Considering Threadability](06-Considering_Threadability.md)
+* [Considering Performance](07-Considering_Performance.md)
+* [Enable Scripting](08-Enable_Scripting.md)
+* [Further Reading](09-Further_Reading.md)
+* [Final Thoughts](10-Final_Thoughts.md)