lftp: add new recipe

LFTP is a sophisticated file transfer program with command line interface.
It supports FTP, HTTP, FISH, SFTP, HTTPS and FTPS protocols.
Every operation in lftp is reliable, that is any non-fatal error is handled and
the operation is retried automatically. So if downloading breaks, it will be
restarted from the point automatically.

Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>