Implement the WCRx1 and WCUx1 via MacKinnon (2021)

[s3alfisc]

• MacKinnon (2021, Econometrics and Statistics)
• R code

[s3alfisc]

• implementation of the WCR11 and WCU11 (only percentile-t pvalues): Done with commit 01b7d71 in port some of boot_algo more #14:
• implementation of the WCR31 and WCU31 (only percentile-t pvalues)