add access to new dust3 parameter and xrb contribution.

[bd-j]

Adding access to some new parameters.

[dfm]

LGTM - your call whether or not we should add a test!

[bd-j]

added a test for dust3. The test for xrb would be slow and I think it's a more specialized use case, so I'm omitting. I think we should do a new release when the tests are green and this is merged. There's some other bells and whistles I'm looking at but those can wait for a later release.

[dfm]

Let me poke at the windows builds and see if I can fix them this afternoon/weekend and then do a release early next week?

[bd-j]

Sounds great, thanks @dfm!