Replase Jetty to Gretty

[nicolaichuk]

you used jetty plugin for gradle web test

https://github.com/xpenatan/gdx-shadertoy/blob/master/dragome/build.gradle

When try run "jettyRun" task, gradle v3.4 write

The Jetty plugin has been deprecated and is scheduled to be removed in Gradle 4.0. Consider using the Gretty (https://github.com/akhikhl/gretty) plugin instead.

It may be worth to use gretty plugin?

https://discuss.gradle.org/t/future-of-jetty-plugin/18722

This plugin is deprecated and will be removed in Gradle 4.0. Consider using the more feature-rich Gretty plugin instead.

https://docs.gradle.org/current/userguide/jetty_plugin.html

[xpenatan]

Sure, jetty is really slow. takes some minutes to compile in my i7 compared with eclipse 8-20 secs

[xpenatan]

done, but still slow. i think its gradle...