Make Hash default constructor, hex constructor, data(), const
operator[] and fromString constexpr. Change fromString to be
non-throwing: it now uses a validity flag and fills the hash with zeros
on parse error instead of throwing. Add a constexpr toHexArray helper
that returns a std::array<char, N*2> for compile-time hex conversion.
Update tests to include <string_view>, use std::string_view, add
constexpr InfoHash usage and a static_assert for the hex array.
Adrien Béraud
d32f51455a