Replace default-parameter with function overloading. (#23)

This is a more futureproof version, should further begin functions be added in the future.

Author: aentinger

src/Braccio++.h

@@ -84,7 +84,8 @@ class BraccioClass
 
   BraccioClass();
 
-  bool begin(voidFuncPtr customMenu = nullptr);
+  inline bool begin() { return begin(nullptr); }
+         bool begin(voidFuncPtr customMenu);
 
   // setters
   MotorsWrapper move(int joint_index) {