Review again the documentation about restart vs. reload

[snicoll]

See http://stackoverflow.com/questions/41455936/one-gradle-thymeleaf-project-reloads-on-resource-change-the-other-relaunches/

Looking at the documentation, we don't make a clear distinction and the doc is a bit confusing with sentences like

Note that certain resources such as static assets and view templates do not need to restart the application.

They don't but the user still needs to update the classpath. We should make that crystal clear at the beginning or something.