rangeslider: refactor draw routine

- use d3 enter/exit/update pattern to handle drawing step
  for creation / deletion and update paths
  -> no longer need a relayout hook !!!
- fix: range slider span depends on axis range
- fix: range slider option now update on relayout
- use coverslip to avoid select axis title

Author: etpinard

src/components/rangeslider/constants.js

@@ -0,0 +1,51 @@
+/**
+* Copyright 2012-2016, Plotly, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+'use strict';
+
+module.exports = {
+
+    // attribute container name
+    name: 'rangeslider',
+
+    // class names
+
+    containerClassName: 'rangeslider-container',
+    bgClassName: 'rangeslider-bg',
+    rangePlotClassName: 'rangeslider-rangeplot',
+
+    maskMinClassName: 'rangeslider-mask-min',
+    maskMaxClassName: 'rangeslider-mask-max',
+    slideBoxClassName: 'rangeslider-slidebox',
+
+    grabberMinClassName: 'rangeslider-grabber-min',
+    grabAreaMinClassName: 'rangeslider-grabarea-min',
+    handleMinClassName: 'rangeslider-handle-min',
+
+    grabberMaxClassName: 'rangeslider-grabber-max',
+    grabAreaMaxClassName: 'rangeslider-grabarea-max',
+    handleMaxClassName: 'rangeslider-handle-max',
+
+    // style constants
+
+    maskColor: 'rgba(0,0,0,0.4)',
+
+    slideBoxFill: 'transparent',
+    slideBoxCursor: 'ew-resize',
+
+    grabAreaFill: 'transparent',
+    grabAreaCursor: 'col-resize',
+    grabAreaWidth: 10,
+    grabAreaMinOffset: -6,
+    grabAreaMaxOffset: -2,
+
+    handleWidth: 2,
+    handleRadius: 1,
+    handleFill: '#fff',
+    handleStroke: '#666',
+};