RFR 8134562: jjs history object should have methods to save/load history to/from given file and also allow reexecution of commands by a call

[Sundararajan Athijegannathan]

Please review http://cr.openjdk.java.net/~sundar/8134562/ for 
https://bugs.openjdk.java.net/browse/JDK-8134562

Thanks,
-Sundar