Add additional helper closures

[JLLeitschuh]

Providing a few of the more commonly used closure types in kotlin would be useful, for example:

open class NoArgKotlinClosure<V : Any>(
    val function : () -> V?,
    owner: Any? = null,
    thisObject: Any? = null) : groovy.lang.Closure<V?>(owner, thisObject) {

    @Suppress("unused") // to be called dynamically by Groovy
    fun doCall() : V? = function()
}

[JLLeitschuh]

Thank you!!!! This will make things so much easier!