Version 2.6.8.0

Now targetting .NET Framework 4.5. Also now referencing PDFSharp version 1.5.5185

Version 2.5.7.1

Added a human-readable error message when a PDF document is encrypted with an unsupported algorithm. This message hopefully explains exactly what the user should do.

Version 2.5.6.0

Upgraded .NET version requirement to 3.5, and also implemented automatic upgrade check.

For more information, see the README.md in the master branch.

Version 2.2.5.0

version-2.2.5.0

Update README.md, so that people actually know how to USE the thing

Version 2.1.4.1

version-2.1.4.1

Validation and optimisations