[ELY-43] Switch from ByteArrayIterator to ByteArrayInputStream
[ELY-43] Switch from CharacterArrayIterator to a class that extends CharArrayReader
[ELY-43] Add support for padding characters when Base-64 encoding and decoding and also add pluggable alphabet support
[ELY-43] Remove SaslBase64.java and add necessary methods to Base64.java so we have only one Base64 class