Added delegated property through map support + tests.

backend.native/tests/codegen/delegatedProperty/lazy.kt

@@ -0,0 +1,9 @@
+val lazyValue: String by lazy {
+    println("computed!")
+    "Hello"
+}
+
+fun main(args: Array<String>) {
+    println(lazyValue)
+    println(lazyValue)
+}

backend.native/tests/codegen/delegatedProperty/map.kt

@@ -0,0 +1,13 @@
+class User(val map: Map<String, Any?>) {
+    val name: String by map
+    val age: Int     by map
+}
+
+fun main(args: Array<String>) {
+    val user = User(mapOf(
+            "name" to "John Doe",
+            "age"  to 25
+    ))
+    println(user.name) // Prints "John Doe"
+    println(user.age)  // Prints 25
+}

backend.native/tests/codegen/delegatedProperty/observable.kt

@@ -0,0 +1,14 @@
+import kotlin.properties.Delegates
+
+class User {
+    var name: String by Delegates.observable("<no name>") {
+        prop, old, new ->
+        println("$old -> $new")
+    }
+}
+
+fun main(args: Array<String>) {
+    val user = User()
+    user.name = "first"
+    user.name = "second"
+}