CLI: use JDK 1.6 to compile the "kotlin" launcher script

"kotlin" is used to run programs compiled by "kotlinc" which supports
emitting JVM bytecode 1.6, so it should also be runnable on JDK 1.6

compiler/cli/cli-runner/cli-runner.iml

@@ -1,11 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <module type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_6" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
     </content>
-    <orderEntry type="inheritedJdk" />
+    <orderEntry type="jdk" jdkName="1.6" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="kotlin-runtime" level="project" />
   </component>

compiler/cli/cli-runner/src/org/jetbrains/kotlin/runner/runners.kt

@@ -77,9 +77,13 @@ class MainClassRunner(override val className: String) : AbstractRunner() {
 class JarRunner(private val path: String) : AbstractRunner() {
     override val className: String =
             try {
-                JarFile(path).use { jar ->
+                val jar = JarFile(path)
+                try {
                     jar.manifest.mainAttributes.getValue(Attributes.Name.MAIN_CLASS)
                 }
+                finally {
+                    jar.close()
+                }
             }
             catch (e: IOException) {
                 throw RunnerException("could not read manifest from " + path + ": " + e.message)