Varvault

There was a bug with the vaulter function, where returning the values in a minivault would bypass type-validation and you could essentially insert a value of any type for a given key into the vault. This has now been fixed and a test has been implemented for it.

Made a fix to log levels in the vaulter function to make sure that the log levels are always configured in post_call. If a vault was used in nested functions, the inner function would reset the log levels, and then the outer function would keep those log levels. This could cause unintended behavior when using debug flag for example.

Patched vault-flag return_key_can_be_missing to actually return a string to identify the flag and not to return none.

Created new vault-flags input_key_can_be_missing and clean_return_keys which replaces input_var_can_be_missing and clean_return_var_keys respectively. The name of these new keys makes more sense and matches the rest of the code better.

Added a new vault flag called return_key_can_be_missing which will allow a vaulter-decorated function to not have to return all keys defined as return-keys. The object returned from the function must be a MiniVault

The initial release of varvault.