SCPUpload/SCPDownload: Space in remote file names behaves differently

Hi,

While it is possible to upload (SCPUploadClient) a file to a remote location containing spaces in its remote filename, this is not possible for download (SCPDownloadClient)

* SCPUploadClient uses ScpCommandLine.EscapeMode.SingleQuote
* SCPDownloadClient uses ScpCommandLine.EscapeMode.NoEscape

Shouldn't both implementations use the same default EscapeMode?

My current workaround is

```
client.newSCPFileTransfer().newSCPDownloadClient().copy(remote, new FileSystemFile(local), ScpCommandLine.EscapeMode.SingleQuote);
```
instead of
```
client.newSCPFileTransfer().download(remote, local);
```