Mario: better mushroom movement

mario/visitors/mushroom_visitor.cpp

@@ -34,11 +34,13 @@ void MushroomVisitor::visit( const SDLPP::RenderObject &obj ) {
         } else if ( from == MARIO_LEFT_SIDE_DETECT ) {
             if(!left && !right) {
                 movement_blockage = obj.getPos();
+                validXPos = movement_blockage.getX() + BLOCK_SIZE;
             }
             left = true;
         } else if (from == MARIO_RIGHT_SIDE_DETECT ) {
             if(!left && !right) {
                 movement_blockage = obj.getPos();
+                validXPos = movement_blockage.getX() - BLOCK_SIZE;
             }
             right = true;
         }

mario/visitors/mushroom_visitor.hpp

@@ -40,10 +40,14 @@ public:
     bool getDeath() {
         return death;
     }
+    double getValidXPos() {
+        return validXPos;
+    }
 
 private:
     bool onGround = false;
     double groundY = 0;
+    double validXPos = 0;
     bool stop = false;
     bool left = false;
     bool right = false;