It would be great to add the functionality to manage custom license types in License Manager.

• Add "Add custom license" button
• Add "Remove license button"
• New/Edit license dialog to enter the license info: shortname, fullname and source (link to license text)

Choose license mandatory. Options:

• A new license type in license manager called "Not valid" i.e. If user choose this license the file is not uploaded/downloaded. Admin can set "Not valid" as default license to make a "valid license" choosing mandatory.
• Checkbox called "force user to choose license"