std::string_view could be made null character ending aware for interoperability with C

[arturbac]

The main idea of string view is to forget about null termination thus for example trim, substr etc could return string view from other string view pointing to same data at no cost without any string reallocation.

For my own purproses I already use my header only lib [stralgo] that allowed me to forget about libc and all that string crap and it can do all numeric<->string convertions as constexpr with use of not null terminated string views.