Added rawdatafallback option to ftpdeploy task.

I was trying to deploy my web project to a ftp server. I activated depends on FTPDeployTask to phing would not just copy everyfile again and again to the ftp server. But everytime I was deploying Phing copied every file to the ftp server (which is annoying if you just want to deploy a small change in a single file). So searched for the bug, and I found a solution.

Net_FTP was unable to parse the file informations from the ftp server (for some reason). But that's not very difficult.
If Net_FTP is not able to parse the raw ftp data, why should we not try to do so. I added a new option to FTPDeployTask (called rawdatafallback, default = false).
If set to "true" the FTPDeployTask is trying to parse the raw data from ftp server if the default list command does not work.
Simply add rawdatafallback="true" to your ftpdeploy task.