• code and pod cleanups
  
• use_ext is now on by default
  
• when use_ext is on, if a loader throws an error, we throw an error
  
• fix case where use_ext is defined and false, but was behaving like
  use_ext => 1
  
• allow loaders to return multiple documents as an array
  
• each plugin now has an is_supported() method which helps us figure out
  if the right modules are available