bootstrap 时间插件 daterangepicker 4.0 添加清空按钮

# Date Range Picker  This date range picker component creates a dropdown menu from which a user can select a range of dates. I created it while building the UI for [Improvely](http://www.improvely.com), which needed a way to select date ranges for reports. Features include limiting the selectable date range, localizable strings and date formats, a single date picker mode, a time picker, and predefined date ranges. ## [Documentation and Live Usage Examples](http://www.daterangepicker.com) ## [See It In a Live Application](https://awio.iljmp.com/5/drpdemogh) ## License The MIT License (MIT) Copyright (c) 2012-2018 Dan Grossman Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.