Refactor command-line interface to kotlin-preloader.jar

Use reasonable defaults for the options: no time profiling, no instrumenters,
empty classpath, 4096 as the class number estimate. Replace 4096 in the
codebase with the constant field.

Keep the old interface intact until the build is bootstrapped and the new one
can be used in all compilation steps

ant/src/org/jetbrains/kotlin/ant/KotlinAntTaskUtil.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ant
 
 import org.apache.tools.ant.AntClassLoader
 import org.jetbrains.kotlin.preloading.ClassPreloadingUtils
+import org.jetbrains.kotlin.preloading.Preloader
 import java.io.File
 import java.lang.ref.SoftReference
 import java.net.JarURLConnection
@@ -54,10 +55,10 @@ object KotlinAntTaskUtil {
         val cached = classLoaderRef.get()
         if (cached != null) return cached
 
-        val myLoader = javaClass.getClassLoader()
+        val myLoader = javaClass.classLoader
         if (myLoader !is AntClassLoader) return myLoader
 
-        val classLoader = ClassPreloadingUtils.preloadClasses(listOf(compilerJar), 4096, myLoader, null)
+        val classLoader = ClassPreloadingUtils.preloadClasses(listOf(compilerJar), Preloader.DEFAULT_CLASS_NUMBER_ESTIMATE, myLoader, null)
         classLoaderRef = SoftReference(classLoader)
 
         return classLoader