0.4.0

• Fix: remove unwanted end-of-line appended to the output when using
  -g option to recover a blob.
• AES encryption support.
  OpenDHT's crypto interface is used as it is already a fundemental
  dependency. This implicates:
  • Key stretchting with argon2;
  • AES-GCM encryption;
• Unit tests.
  • New dependency on the Catch library.
  • Making use of travis for running them.
• Use of Msgpack for serialization of data before sending with OpenDHT.
  Backward compatibility with 0.3.3 prior to this is maintained.
• Better log encapsulation.
• GPG crypto support (encrypting, signing, decrypting and verifying data).
  It uses GpgME C++ wrapper around the C library GpgME. This library handles
  OpenPGP crypto and prompts for the user input for passphrase when needed.
• More strict dependency on curlpp>=0.8.1 and nlohmann-json=2.1.1
• autotools: various improvements in using libraries variables
• CMake: update and fix some bugs (#11, #13)
• parse dpaste:<code> syntax