Gradle wrappers

[Johan Vos]

Hi,

Using Gradle wrappers has been discussed a number of times, but there was
never a clear resolution afaik.

Andres opened an issue for using gradle wrappers:
https://github.com/javafxports/openjdk-jfx/issues/23

I personally like gradle wrappers myself, it makes it easier to automate
builds etc. If developers really want to use a specific (other) gradle
version, it is of course very well possible to do so.

Opinions?

- Johan