Merge branch 'release/0.4'

* release/0.4:
  Increase version number
  Documentation update
  Adds a tool for generating keys
  Updated tests and added imports/exceptions
  Updated encryption/decryption functions to use AES128/CBC instead of AES128/ECB
  Prepare new development branch
Documentation fix
Merge branch 'hotfix/0.4.0.1' into develop

* hotfix/0.4.0.1:
  Documentation fix