* Make is_encrypted_file handle both files opened in text and binary mode
On python3, by default files are opened in text mode. Since we know
the encoding of vault files (and especially the header which is the
first set of bytes) we can decide whether the file is an encrypted
vault file in either case.
* Fix is_encrypted_file not resetting the file position
* Update is_encrypted_file to check that all the data in the file is ascii
* For is_encrypted_file(), add start_pos and count parameters
This allows callers to specify reading vaulttext from the middle of
a file if necessary.
* Combine VaultLib.encrypt() and VaultLib.encrypt_bytestring()
* Change vault's is_encrypted() to take either text or byte strings and to return False if any part of the data is non-ascii.
* Remove unnecessary use of six.b
* Vault Cipher: mark a few methods as private.
* VaultAES256._is_equal throws a TypeError if given non byte strings
* Make VaultAES256 methods that don't need self staticmethods and classmethods
* Mark VaultAES and is_encrypted as deprecated
* Get rid of VaultFile (unused and feature implemented in a different way)
* Normalize variable and parameter names on plaintext, ciphertext, vaulttext
* Normalize variable and parameter names on "b_" prefix when dealing with bytes
* Test changes:
* Remove redundant tests( both checking the same byte string)
* Fix use of format string without format operator
* Enable vault editor tests on python3
* Initialize the vault_cipher for VaultAES256 testing in setUp()
* Make assertTrue and assertFalse take the actual method calls for
better error messages.
* Test that non-ascii byte strings compare correctly.
* Test that unicode strings and ints raise TypeError
* Test-specific:
* Removed test_methods_exist(). We only have one VaultLib so the
implementation is the assurance that the methods exist. (Can use an abc for
this if it changes).
* Add tests for both byte string and text string input where the API takes either.
* Convert "assert" to unittest assert functions or add a custom message where
that will make failures easier to debug.
* Move instantiating the VaultLib into setUp().
