URIUtils::AddSlashAtEnd: remove CStdString
URIUtils: remove CStdString from HasSlashAtEnd and RemoveSlashAtEnd
AliasShortcutUtils: remove CStdString
URIUtils: add 'FixSlashesAndDups()' function
[win32] WIN32Util: add "ConvertPathToWin32Form()" function
[win32] WINSMBDirectory: Update, remove CStdString
[win32] WINFileSMB::GetLocal: update, remove CStdString
HDDirectory: error checks, update for Win32
HDFile: remove CStdString, update for win32
Merge pull request #3408 from Karlson2k/win32_fix_path_slashes_small

Win32: fix path slashes (diet version)