Have an option to remove NaN from the inputs

[antononcube]

It would be nice to have optional removal of NaN's (or Any, or Whatever) specifications for package's core functions (mean, median, etc.).

For example:

my @list = (1, 3, 3, NaN, 33, 2323);
mean(@list):remove-nan

should produce the same result as:

mean(@list.grep({ !$_.isNaN }).List)

Note that this would also make "nicer" the functions summary and hist.