Change to Facebook JS SDK link

[oomlaut]

It appears that http://connect.facebook.net/en_US/sdk.js is erratically available, in favor of http://connect.facebook.net/en_US/all.js.

This would need to be updated in angular-facebook.js line 589:

var src           = '//connect.facebook.net/' + settings.locale + '/sdk.js',

to prevent the console error:

GET http://connect.facebook.net/en_US/sdk.js net::ERR_CONNECTION_RESET

[Jorgelig]

all.js is deprecated: https://stackoverflow.com/a/38481020/845580