Allow keypaths to preserve order

[mucmch]

Given a benedict dictionary d, invoking d.keypaths() will return all paths in a sorted order.

There are cases where this is an undesired behavior and is caused by kps.sort() in benedict.core.keypaths.py.

I would propose a new parameter "sorted" to keypaths that allows to disable this line of code.

[fabiocaccamo]

@mucmch I agree with adding a "sorted" parameter to keypaths method (defaults to True for backward compatibility).

Do you want to submit a PR with a couple tests?

[mucmch]

Did a simple implementation, but do not manage to commit to Github. I attached a patch file.

keypaths_order.patch

[kotfu]

New user of benedict here, and I could benefit from this "sorted" parameter. I'll submit a PR shortly.

[fabiocaccamo]

@kotfu thank you very much for the PR!
@mucmch parameter available in 0.34.1.