4.0.0 - New major version

New features:

• Added the possibility to define input keys through the name of the parameters in the signature of the function. It essentially comes down to calling a parameter the same as the name of a key in the keyring and making sure the flag VaultFlags.use_signature_for_input_keys is defined. This can reduce boilerplate, but does make it harder to track the usage of certain keys, which is why it will never be the default behavior of varvault.

Other changes:

• Updated the conclusion section of the README.md.
• Reworked the filehandlers API and simplified the JsonFileHandler slightly.
  • The filehandler now holds the state and keeps track of it, rather than varvault itself keeping track of the state.
• Made changes to the vaultstructs API to change the name of the abstract method to create which is a lot less cumbersome of a function name.
• Made significant cleanup of code, mostly in vault.py to make it easier to work with, and to read and comprehend.
• Renamed filehandler.py to resource.py as that is more what it is than a filehandler, even if that will most likely be what it will be used for.