Move Epsilon progam execution to doLast block in Gradle

[kolovos]

Reported by @agarciadom on Slack.

I noticed an issue in the Gradle files generated by the Epsilon Playground. The actual transformation should be put in a doLast block, so it will only be run in the execution phase of Gradle. Otherwise, it runs in the configuration phase (which is executed by the Gradle support in IDEs like Visual Studio), which will create issues if someone wanted to use remote debugging capabilities. So something like this:

task run {
    dependsOn tasks.setupEpsilonTasks
    doLast {
      // Load the MarkingMate model
      ant.'epsilon.emf.loadModel'(name: 'M', modelfile: 'model/markingmate.xml', metamodelfile: 'model/markingmate.ecore')
      ant.'epsilon.evl'(src: 'epsilon/markingmate.evl'){
        model(ref: 'M')
      }
    }
}