#141 Replace lftpget with lftp

[monipol]

Package manger version: 0.28.7

Patches NetAccess.pm to replace lftpget with lftp (DownloadMethod).

There is a somewhat ugly hack in this patch because lftp needs a closing quotation mark _after_ the URL is appended to the command.

[monipol]

This patch implements feature request #2723816.

https://sourceforge.net/tracker/?func=detail&aid=2723816&group_id=17203&atid=367203

[monipol]