Update Gradle wrapper to 4.1 and minor cleanup for Gradle build script

Author: stephan-gh

build.gradle.kts

@@ -27,7 +27,7 @@ plugins {
     id("org.jetbrains.kotlin.jvm") version "1.1.3-2" // kept in sync with IntelliJ's bundled dep
     groovy
     idea
-    id("org.jetbrains.intellij") version "0.2.15"
+    id("org.jetbrains.intellij") version "0.2.17"
     id("net.minecrell.licenser") version "0.3"
 }
 
@@ -50,7 +50,7 @@ val processResources: AbstractCopyTask by tasks
 val test: Test by tasks
 val runIde: JavaExec by tasks
 val publishPlugin: PublishTask by tasks
-val clean: Task by tasks
+val clean: Delete by tasks
 
 configurations {
     "kotlin"()
@@ -244,15 +244,12 @@ val generate = task("generate") {
 
 java.sourceSets[SourceSet.MAIN_SOURCE_SET_NAME].java.srcDir(generate)
 
+// Remove gen directory on clean
+clean.delete(generate)
+
 // Workaround for KT-16764
 compileKotlin.inputs.dir(generate)
 
-// Workaround problems caused by separate output directories for classes in Gradle 4.0
-// gradle-intellij-plugin needs to be updated to support them properly
-java.sourceSets.all {
-    output.classesDir = File(buildDir, "classes/$name")
-}
-
 runIde {
     maxHeapSize = "2G"
 
@@ -264,12 +261,6 @@ runIde {
     }
 }
 
-val cleanGen = task<Delete>("cleanGen") {
-    delete = setOf(file("gen"))
-}
-
-clean.dependsOn(cleanGen)
-
 inline operator fun <T : Task> T.invoke(a: T.() -> Unit): T = apply(a)
 fun DependencyHandlerScope.kotlinModule(module: String) = kotlinModule(module, kotlinVersion) as String
 fun intellijPlugin(name: String) = mapOf(

gradle/wrapper/gradle-wrapper.jar

@@ -1,6 +1,5 @@
-#Wed Jul 26 23:42:24 CDT 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-bin.zip

gradle/wrapper/gradle-wrapper.properties

@@ -33,11 +33,11 @@ DEFAULT_JVM_OPTS=""
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
 
-warn ( ) {
+warn () {
     echo "$*"
 }
 
-die ( ) {
+die () {
     echo
     echo "$*"
     echo
@@ -155,7 +155,7 @@ if $cygwin ; then
 fi
 
 # Escape application args
-save ( ) {
+save () {
     for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
     echo " "
 }