backup 20180718

修正net45下一个缺失引用的错误

2.5.1

Fix httpcient timeout issue

2.5.0

修改ReContent为虚方法, 让用户可以扩展读取的方法(编码问题等)

2.4.5

开始用回本命package id

2.4.3

异常信息不应该用.结尾

2.3.9

1. WebDriverDownloader null reference issue
2. Remove NullPipeline and use ConsolePipeline as default

2.3.8

Merge pull request #35 from dotnetcore/2.3.8

upgrade package version