增加drag组件

src/drag/index.js

@@ -0,0 +1,14 @@
+import { css, html, Component, nextTick, styleMap } from '@bd/core'
+
+import Core from './core.js'
+
+class Drag extends Component {
+  static props = {
+    overflow: false,
+    limit: 'window',
+    'disable-x': false,
+    'disable-y': false
+  }
+}
+
+Drag.reg('drag')