add interface DrawerState

src/main/java/shape/tp5/DrawerState.java

+package shape.tp5;
+
+import javafx.scene.canvas.GraphicsContext;
+
+
+public interface DrawerState {
+    public void mousePressed(DrawerContext context, double x, double y);
+    public void mouseReleased(DrawerContext context, double x, double y);
+    public void mouseMoved(DrawerContext context, double x, double y);
+    public void paint(DrawerContext context, GraphicsContext graphicsContext);
+
+}
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