Feature request: Add support for choosing C++ standard for cppreference pages

[aborzunov]

Some part made a long way while standard evolved. Default cppreference contains reference for all standards with "until" and "since" labels.
This makes page quite hard to read, because there is a lot of irrelevant overloads.
That is why there is option to choose cpp-standard and display only reference for it.

It would be greate to support such feature in zeal!

This how default cppreference looks and how it looks after choosing your standard: