EVERYONE: License of vis.js

Currently vis.js is licensed under the Apache 2.0 License. This license is incompatible with for example the GPL v2 licenses (though it is compatible with v3).

I'm not sure how big this issue really is. But in order to better serve our users, we are considering whether it is useful to change the license. A few things are important for us:

1. as much as possible freedom for the user
2. protection for the user (like against patent threats or changing the license conditions later on)
3. keep attribution (honor the people and our company investing so much in this library)

While MIT is a nice fit for (1), Apache 2.0 better serves (2) and (3). We could choose one of the two, or even choose a dual license allowing both.

Do you have any opinion on the licencing of vis.js?