Add a new “stencil8” pixel format for Canvases (resolves issue #1003).

Also fixed Canvas MSAA (resolves issue #1271).

stencil-formatted Canvases can’t be drawn, and can only be used as the value for a new ‘depthstencil’ field to the table-argument variant of love.graphics.setCanvas.

--HG--
branch : minor

src/modules/graphics/opengl/SpriteBatch.cpp

@@ -76,7 +76,7 @@ void SpriteBatch::draw(Graphics *gfx, const Matrix4 &m)
 		}
 
 		if (Shader::current)
-			Shader::current->checkMainTextureType(texture->getTextureType());
+			Shader::current->checkMainTexture(texture);
 	}
 
 	OpenGL::TempDebugGroup debuggroup("SpriteBatch draw");