RFR: (JDK-8005406) HTTP server implementation should use Base64 API

[Mark Sheppard]

Hi,

Request for review of JDK-8005406, this time!

This is the second in a series of refactorings which migrate base64 support in various
packages to utilize the base64 support from java.util.Base64.

This is the modification of com.sun.net.httpserver.BasicAuthenticator.java
to use java.util.Base64.

This makes changes to the BasicAuthenticator class to use java.util.Base64.Decoder, and removes a
package private Base64 class.

webrev located at
http://cr.openjdk.java.net/~chegar/8005406

regards
Mark Sheppard