Add Database constructor for filesystem::path #296

[ptrks]

Added an additional constructor in Database.h that accepts a std::filesystem::path object. Also updated the ctorExecCreateDropExist unit test in Database_test.h which will test the new constructor if the detected compiler supports c++17.

[coveralls]

Coverage remained the same at 100.0% when pulling 340262a on ptrks:database_std_filesystem into 3fcb352 on SRombauts:master.

[SRombauts]

Thanks a lot for providing this!
I was actually certain I had it merged two days ago, but I apparently had stopped before submitting....

[ptrks]

Of course!

[SRombauts]

Have you seen issue #317 that it apparently fails on vs2019 (and proposed fix #318

[chronoxor]

Possible fix is to convert std::wstring to utf-8 based string:

std::string ToUTF8(const std::wstring& wstr)
{
#if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__)
    std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> convert;
    return convert.to_bytes((char16_t*)wstr.data(), (char16_t*)wstr.data() + wstr.size());
#elif defined(unix) || defined(__unix) || defined(__unix__) || defined(__APPLE__)
    std::wstring_convert<std::codecvt_utf8<wchar_t>> convert;
    return convert.to_bytes(wstr.data(), wstr.data() + wstr.size());
#elif defined(_WIN32) || defined(_WIN64)
    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> convert;
    return convert.to_bytes(wstr.data(), wstr.data() + wstr.size());
#endif
}

[Chronial]

As sum01 remarked, the u8string() method already gives a utf-8 encoded string on all platforms. I implemented that in #319.