UI Examples Update (Widget Demo v7.1.5 and MWT Examples v2.4.1)

Hello MicroEJ enthusiasts,

We updated UI examples to have smoother scrolling when using containers, we also simplified the implementation of the BufferedImagePool class.

The Widget demo is now using the latest MWT version and several pages were added (a CircularSlider widget page, a DoubleTemperatureSlider widget page, and a FixedGrid page).

Happy Coding!
The MicroEJ Team.