fixed: split non-template class in header/implementation
fixed: remove selfinclude from header
[UnrarXLib] drop use of URIUtils::GetExtension in favour of simple strrchr, ref dcd92b3769a0e4db0fceb568f9e3ccd71fbc4b74
[dllloader] have LibraryLoader hold std::string's
[fileitem] make the string constructor of CFileItem(List) explicit
[stdstring] drop assignment/append/construction from non-char pointers, and remove usage of assign from char