Encodes/decodes 7-bit strings according to RFC 2045.
See the following link for reference:
Decodes a 7-bit encoded string
Encodes a string into a 7-bit encoded string
Decodes a 7-bit encoded string.
Encodes a string into a 7-bit encoded string.
Raises if any character isn’t in the 7-bit ASCII range 1..127.