TFisher 0.2.1

• New maintainer: Zheyang Wu (zheyangwu@wpi.edu).
• The package now has a public repository and issue tracker: https://github.com/ZWuLab/TFisher. Added Authors@R, URL, and BugReports fields to DESCRIPTION.
• Updated the reference in Description to the published paper (Zhang, Tong, Landers and Wu, 2020, The Annals of Applied Statistics, doi:10.1214/19-AOAS1302).
• Removed the unused LazyData field.
• No changes to functions or computations.