RFR: JDK-8230521: rename --output/-o option and add default value (".")

[Alexander Matveev]

Please review the jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

- Renamed "--output" to "--dest" and made it optional with default to ".".

[1] https://bugs.openjdk.java.net/browse/JDK-8230521

[2] http://cr.openjdk.java.net/~almatvee/8230629/webrev.00/

Thanks,
Alexander