title: CCMotionStreak working with CCMoveTo
body: <p>I'm trying to use the CCMotionStreak to draw a path with a CCSprite.</p>
  
  <p>Init:</p>
  
  <pre><code>CCMotionStreak* streak;
  streak = [CCMotionStreak streakWithFade:100 minSeg:1 image:@"streak.png" width:5
      length:3 color:ccc4(0, 255, 255, 255)];streak.position = self.theHero.heroSprite.position;
  </code></pre>
  
  <p>When a touch ends:</p>
  
  <pre><code>-(void) ccTouchEnded:(UITouch*)touch withEvent:(UIEvent *)event
  {
      [self unschedule:@selector(doStep:)];
  
      CGPoint touchLocation = [touch locationInView: [touch view]];
      CGPoint curPosition = [[CCDirector sharedDirector] convertToGL:touchLocation];
  
      [self.theHero.heroSprite stopAllActions];
          //cal the duration, speed is set to 85.0f
      float du = ccpDistance(self.theHero.heroSprite.position, curPosition) / 85.0f;
      [self.theHero.heroSprite runAction:[CCMoveTo actionWithDuration:du
                                                             position:curPosition]];
  
      [self schedule:@selector(doStep:)];
  }
  
  - (void)doStep:(ccTime)delta
  {
          //update the position
      [streak setPosition:self.theHero.heroSprite.position];
  }
  </code></pre>
  
  <p>When I run the demo, the CCMotionStreak draws a line beautifully the first time
  I touched the screen, then when the sprite stops, I tried to touch somewhere else
  on the screen and the CCMotionStreak draws a second line successfully but I noticed
  that the CCMotionStreak lines "shakes" a little bit(offset a little bit) during the sprite moving and then "shakes back to normal position" when the sprite stops moving.</p>
  
  <p>I hope someone can give me a hint, thanks :) </p>