Support for distributing arbitrary arguments to Locust [Proposal]

[mlromramse]

Since it now is possible to write your own Locusts, which we have started to do it would be appreciated if the command line arguments not directed to locust.main or HttpLocust could be passed along into the Locust derivate of choice.

If you for instance create a Locust that doesn't use Http the host argument is not needed. Still this is the only argument you can pass to your Locust class.

My suggestion is that *args and **kwargs is taken from the command line arguments and added to the Locust.__init__.

In this way you can build your own locusts and control them from the command line alone.

[cyberw]

Closing due to lack of activity. Let me know if this is still an issue.