Easy Digital Downloads - Per Product Emails 2.0.1

Fix: Prevent a PHP error when no product IDs that need custom emails are found.
Fix: Allow attachments to be included when the EDD_Emails class is used.

= 1.1.3 =
* Fix: There were errors if Software Licensing was not active. Here all SL functions are moved to an integration folder with a check to make sure it is active.

= 1.1.2 =
* Fix: Email formatting not properly preserved when saving.