Base64

```
public class Base64
extends java.lang.Object
```
JMake needs to run against old versions of Java, that may not have JAXB's javax.xml.bind.DatatypeConverter. And we don't want JMake to depend on third-party external libraries, especially not just for this. So we implement a lightweight Base64 converter here ourselves. Note that sun.misc.BASE64Encoder is not official API and can go away at any time. Plus it inserts line breaks into its emitted string, which is not what we want. So we can't use that either.

Methods
Modifier and Type	Method and Description
`static byte[]`	`decode(char[] in)`
`static char[]`	`encode(byte[] in)`

public static char[] encode(byte[] in)

public static byte[] decode(char[] in)

Class Base64