-X... and -X? options to search for properties.

I can never remember the names of various JRuby options - even my own! This allows you to search for them, either by prefix or substring. Are we interested in having this functionality?

Examples:

```
$ bin/jruby -Xdump?
compile.dump=false
jit.dumping=false
ffi.compile.dump=false
thread.dump.signal=USR2
dump.variables=false
```

```
$ bin/jruby -Xir...
ir.debug=false
ir.profile=false
ir.compiler.debug=false
ir.visualizer=false
ir.unboxing=false
ir.passes=null
ir.jit.passes=null
ir.reading=false
ir.reading.debug=false
ir.writing=false
ir.writing.debug=false
ir.inline_passes=null
```

I've modified the `.sh` and `.bash` launchers. Is there anything else I need to modify to pass these arguments through?