VSIPL16 — 'Explicit alias' to clarify view copy semantics

In my previous issue, I stated with regards to clarifying the semantics
of a "View v(w)" statement: "Unfortunately this is not possible with the
alias case, but we can at least resolve it for the copy case.

This is not actually true. We could define an alias() function (or
method) on a View which returns a unspecified type, and then a View
constructor that accepts that type as input and either creates an alias
to the precursor view or throws a compile error. Thus, you could write

View v(alias(w));

and know that, if it compiles, you are guaranteed to get a true alias.