Added multisampling to Renderer::Feature enum.

src/Renderer.h

@@ -92,6 +92,14 @@ class MAGNUM_EXPORT Renderer {
             LogicOperation = GL_COLOR_LOGIC_OP,
             #endif
 
+            #ifndef MAGNUM_TARGET_GLES
+            /**
+             * Multisampling (enabled by default)
+             * @requires_gl Always enabled in OpenGL ES.
+             */
+            Multisampling = GL_MULTISAMPLE,
+            #endif
+
             #ifndef MAGNUM_TARGET_GLES
             /**
              * Depth clamping. If enabled, ignores near and far clipping plane.