Function to_upper_case_loc

include/fplus/string_tools.hpp:155–163

// to_upper_case_loc(locale("ru_RU.utf8"), "cYrIlLiC КиРиЛлИцА") == "CYRILLIC КИРИЛЛИЦА"
template <typename String>
String to_upper_case_loc(const std::locale& lcl, const String& str)
{
    typedef typename String::value_type Char;
    return transform([&lcl](Char c) -> Char {
        return static_cast<Char>(
            std::toupper(c, lcl));
    },
        str);
}

// API search type: to_string_fill_left : (Char, Int, a) -> String
// fwd bind count: 2