do not presume a default order-by. publisher may set his or her own default inside the comments tool at developers.facebook.com
Merge pull request #417 from niallkennedy/comments-box-order

always show Comments Box order by property if set
do not call session_start on WP_Facebook initialization
Merge pull request #418 from niallkennedy/no-session

do not call session_start on WP_Facebook initialization
update POT based on current plugin strings
Merge pull request #419 from niallkennedy/gettext-pot

update POT based on current plugin strings
Merge remote-tracking branch 'upstream/master'