Log Message:
Update to 3062.100

Upstream changes:
2020-01-24  Martin Maechler  <maechler@stat.math.ethz.ch>

	* DESCRIPTION (Version): 3062.100 ;  using Authors@R

	* R/utils-head.R: tail.matrix() in R-devel uses 'keepnums'.

	* R/timeSeries-readSeries.R (et all): do *NOT* use
	  `if(class(.) == "timeSeries")` but use `inherits(*, "...")` !!

	* R/methods-plot.R (.plotTimeSeries): fix wrong logic in
	  `if(.. && at == "auto")` when `at` can be a vector (!)

	* R/aaa-utils.R (`%||%`): utility, to be used extensively in
	* R/methods-plot2.R (.xtplot.timeSeries).