u02/tool_base: Add draw with three points

u02/include/tool_base.h

@@ -41,6 +41,8 @@ public:
   virtual void draw(int x, int y);
   // Draw with two points provided
   virtual void draw(int x0, int y0, int x1, int y1);
+  // Draw with three points provided
+  virtual void draw(int x0, int y0, int x1, int y1, int x2, int y2);
 
   // Get the shape that this tool will draw
   const ToolShape get_shape() const;

u02/src/tool_base.cpp

@@ -29,6 +29,12 @@ void tool_base::draw(int from_x, int from_y, int to_x, int to_y) {
   // this method if needed
 }
 
+// Draw with three points provided
+void tool_base::draw(int x0, int y0, int x1, int y1, int x2, int y2) {
+  // Nothing implemented here. Children of this class can implement
+  // this method if needed
+}
+
 // Get the shape that this tool will draw
 const ToolShape tool_base::get_shape() const { return shape; }