Added a way for love's reference-counted objects to be released more safely in some situations (e.g. setters)

src/modules/graphics/opengl/Graphics.cpp

@@ -543,8 +543,7 @@ Color Graphics::getBackgroundColor() const
 
 void Graphics::setFont(Font *font)
 {
-	if (currentFont != 0)
-		currentFont->release();
+	Object::AutoRelease fontrelease(currentFont);
 
 	currentFont = font;
 

src/modules/graphics/opengl/ParticleSystem.cpp

@@ -193,8 +193,7 @@ void ParticleSystem::remove(particle *p)
 
 void ParticleSystem::setImage(Image *image)
 {
-	if (this->image != 0)
-		this->image->release();
+	Object::AutoRelease imagerelease(this->image);
 
 	this->image = image;
 	this->image->retain();

src/modules/graphics/opengl/SpriteBatch.cpp

@@ -176,8 +176,9 @@ void SpriteBatch::unlock()
 
 void SpriteBatch::setImage(Image *newimage)
 {
+	Object::AutoRelease imagerelease(image);
+
 	newimage->retain();
-	image->release();
 	image = newimage;
 }