RFR 8148316: jshell tool: Configurable output format

[Robert Field]

Bug:
     https://bugs.openjdk.java.net/browse/JDK-8148316

Webrev:
     http://cr.openjdk.java.net/~rfield/8148316v1.webrev/

Some example output configurations (Open with /open):
     http://cr.openjdk.java.net/~rfield/formats/arrowResultNlMeta.jsh
     http://cr.openjdk.java.net/~rfield/formats/dan.jsh
     http://cr.openjdk.java.net/~rfield/formats/brian.jsh

-Robert