rhbz1157359 - fix a few java client issues

- --version or -v gives no output (due to non-flushed buffered output)
- single --help or help or -h not giving a list of commands (same as above)
- --logHttp is not recognized (annotation at wrong place). Also changed it to --log-http to follow convention
- redirect will produce friendlier error message
Oh, I see.  They were repeated in the implementation class, which does seem redundant.  I think args4j may be able to pick up annotations from the interface, so perhaps it would be better to keep them here, and remove them from the Impl.  (That way, when you're coding the Maven client, you can browse to the interface and see the command-line args/descriptions, thus making it easier to keep them in sync with Maven.)