* Once cli args are parsed, they're constant. So, save the parsed args
into the global context for everyone else to use them from now on.
* Port cli scripts to use the CLIARGS in the context
* Refactor call to parse cli args into the run() method
* Fix unittests for changes to the internals of CLI arg parsing
* Port callback plugins to use context.CLIARGS
* Got rid of the private self._options attribute
* Use context.CLIARGS in the individual callback plugins instead.
* Also output positional arguments in default and unixy plugins
* Code has been simplified since we're now dealing with a dict rather
than Optparse.Value
