Canvases can now be used in SpriteBatches, ParticleSystems, and Meshes (resolves issue #782).

Canvases and Images are now subclasses of the new Texture class.
Added setTexture and getTexture methods for Meshes, ParticleSystems, and SpriteBatches (the old set/getImage methods are deprecated but not removed.)
Canvas texture coordinates are no longer flipped.

src/modules/graphics/opengl/Polyline.cpp

@@ -327,6 +327,8 @@ Polyline::~Polyline()
 
 void Polyline::draw()
 {
+	gl.prepareDraw();
+
 	// draw the core line
 	gl.bindTexture(0);
 	glEnableClientState(GL_VERTEX_ARRAY);