Discuss about the deprecation warning in the README file and update it

[aalex]

In dde2acf a message has been added to the README file for the project.

See dde2acf#commitcomment-86226021

Discussion

It would be best to discuss it with the other developers before committing a message like this in the main README file of the project. At least, asking for some code reviews would have been appropriate.

There are plans to fund the development efforts for MapMap, and there is a lot of interest for the project, so I would not say that the project is dead.

Therefore, I think that this message should be removed until a discussion has happened. And then, a discussion about this should be planned.

[aalex]

@sofian See my comments above.