Added stack type enums to love.graphics.push (resolves issue #906.) Current enums are "transform" and "all". "transform" is the default (for compatibility.) When love.graphics.push("all") is used, love.graphics.pop() will restore all love.graphics module state to what it was when push was called.

Updated the graphics code to use a custom matrix stack rather than OpenGL1's APIs.

src/modules/graphics/opengl/ParticleSystem.cpp

@@ -843,11 +843,11 @@ void ParticleSystem::draw(float x, float y, float angle, float sx, float sy, flo
 
 	Color curcolor = gl.getColor();
 
-	glPushMatrix();
-
 	static Matrix t;
 	t.setTransformation(x, y, angle, sx, sy, ox, oy, kx, ky);
-	glMultMatrixf((const GLfloat *)t.getElements());
+
+	OpenGL::TempTransform transform(gl);
+	transform.get() *= t;
 
 	const Vertex *textureVerts = texture->getVertices();
 	Vertex *pVerts = particleVerts;
@@ -901,8 +901,6 @@ void ParticleSystem::draw(float x, float y, float angle, float sx, float sy, flo
 
 	texture->postdraw();
 
-	glPopMatrix();
-
 	gl.setColor(curcolor);
 }