Update README.md, mention how to run the jar

Also mention gradlew.bat for Windows.

README.md

@@ -11,9 +11,9 @@ You will find some [basic instructions](https://guide.openrndr.org/setUpYourFirs
 
 ## Gradle tasks
 
- - `run` runs the TemplateProgram
- - `jar` creates an executable platform specific jar file with all dependencies
- - `jpackageZip` creates a zip with a stand-alone executable for the current platform (works with Java 14 only)
+ - `./gradlew run` runs the TemplateProgram (Use `gradlew.bat run` under Windows)
+ - `./gradlew shadowJar` creates an executable platform specific jar file with all dependencies. Run the resulting program by typing `java -jar build/libs/openrndr-template-1.0.0-all.jar` in a terminal from the project root.
+ - `./gradlew jpackageZip` creates a zip with a stand-alone executable for the current platform (works with Java 14 only)
 
 ## Cross builds