Changes Hipster methods to use named parameters to improve readability.

[tiagofsilva]

• This PR breaks backwards compatibility with the previous version of the Hipster class.
• This is just a fair simple refactoring on one class and its test. That's why I didn't create any extra tests as specified in the contributing.md document.

[stympy]

I'm going to hold off on this one until I'm ready for a major release to break backwards compatibility. In that release we'll change everything to use named parameters.

[tiagofsilva]

Great, @stympy! Knowing that, I'll be working on changing more classes to named parameters then.

[vbrazo]

Since we're migrating the objects to namespaces #1318, we'll change the arguments to keywords/named params while adding the namespaces. I think it'd be a better idea to concentrate all the changes in this transition instead of doing things separately. Thanks for opening this PR and suggesting this change.