Examine command line options for consistency, and possible move to GNU style

java, javac, jlink, jar, jmod, ... have been updated in JDK 9 to add new options for modules. There are several inconsistencies, for example java and javac have -modulepath, whereas jlink and jmod have --modulepath. In general, we need to see where the command-line options are going and how we move to GNU style in a consistent way.