Support Model methods with no parameters

[interDist]

We have a bunch of methods on our model that we would like to expose in the GeoJSON. Currently we had to add a bunch of properties to the model to provide these values (all of these properties just calling into the bound methods already present on the model...).

It would be nice to have the ability to include callable methods with no parameters (that is, only self). Is this something the project maintainers would like to include? Are there any pitfalls / possible conflicts / discouragements to implement this?

[Gagaro]

Hi,

I don't have time to improve this package, but feel free to implement it and start a PR. I'll gladly review and merge it.

I don't see any possible issue if this is correctly tested.