Vigenere Cypher implementation in python 3.5
Example usage:
>>> vig = VigenereCypher()
>>> cypher = vig.encrypt('secret', 'this is a sample text')
>>> print(cypher)
'LLKJ BK C WTETNV MWBV'
>>> plain_text = vig.decrypt('secret', cypher)
>>> print(plain_text)
'THIS IS A SAMPLE TEXT'