- Now also compatible with background session
- added delegate notify (success, progress, failure) to FTP
- added `FTPFileProvider.useAppleImplementation`, allows developer choose to use apple download task instead of custom implementation
- enabling to download non-text files in FTP
- implementation of `url(of:) in FTP
- various fixes in error reporting
- disabled closing streams in ftpQuit() due to crash
- All errors from local provider is now from Cocoa error domain. No URL domain anymore.
- All errors from WebDAV/OneDrive/Dropbox conform to FileProviderHTTPError
- code refactoring for RemoteOperationHandle usage and description
- bug fix: move operation in Dropbox provider did copy
- bug fix: dynamic inProgress result for RemoteOperationHandle