Fix planet-lab host selection scripts.

Update of the workflow in README; remove obsolete scripts; select hosts from planet-lab REST API and then based on bandwidth check

Change-Id: Ife9c2119f20c4c91f60042f827c375a365753a69
Reviewed-on: http://naan.mimuw.edu.pl:8001/89
Tested-by: Nebulostore Nebulostore <nebulostore@gmail.com>
Reviewed-by: Bolek Kulbabinski <bkulbabinski@gmail.com>