RFR: JDK-8183579: refactor and cleanup launcher help messages

[Kumar Srinivasan]

Hi,

Please review refactoring and clean up of the java launcher's help/usage
messages.

The highlights of the changes are as follows:

1. Helper.java: is renamed from LauncherHelper.java, simpler name,
     containing mostly methods to help with class loading, module 
assistance etc.

2. OptionHelper.java: moved those methods in Helper.java, pertaining
     to option printing, to this class.

3. Options.java: is heavily inspired by javadoc's option management, it
     is very structured, and makes the resources much  simpler to manage.

4. Modified the options descriptions to be _more consistent_,
     keeping in mind, these options have been in there for eons.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8183579

Webrev:
http://cr.openjdk.java.net/~ksrini/8183579/webrev.00/

java -help output:
http://cr.openjdk.java.net/~ksrini/8183579/help.txt

java -X output:
http://cr.openjdk.java.net/~ksrini/8183579/x-help.txt

Thanks
Kumar