Adding GET to the curl options after the session is handled and reversing the arguments in array_diff were the main issues
Adding real support for series
Merged pull request from david-treblig and others

- Script is meant to be a CLI script, not in browser, so
  I added the LD_CLI constant
- Changed to lesson_id/series ID still conflict need to
  resolve later
- Changed to video page links required shift in output file names
- Added a catch for not subscribed, will put that earlier later
- Added some spacing for succes/fails when newline is present