高仿小米时钟，同步手机时间精确到毫秒
支持的属性有：时钟背景色、亮色（用于分针、秒针、渐变终止色）、暗色（圆弧、刻度线、时针、渐变起始色）、小时文本的字体大小
Copyright 2016 Owen Chan
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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