Changes to unit tests for tslm and HoltWinters

CRAN v7.0

Switched to preferred CRAN URLs for package

Switched to preferred CRAN URLs for package

Updated contributors list

Made auto.arima more robust to prevent TSPred breaking

Made allow.multiplicative.trend=FALSE the default in ets()

Correction to last commit

BoxCox.lambda is now robust to missing values.

Fixed code/doc mismatches in Acf and tsdisplay