generate calls to overloaded binary operators and infix calls

idea/testData/codegen/classes/overloadBinaryOperator.jet

@@ -0,0 +1,25 @@
+import java.util.*
+
+class ArrayWrapper<T>() {
+    val contents = ArrayList<T>()
+
+    fun add(item: T) {
+       contents.add(item)
+    }
+
+    fun plus(b: ArrayWrapper<T>): ArrayWrapper<T> {
+        val result = ArrayWrapper<T>()
+        result.contents.addAll(contents)
+        result.contents.addAll(b.contents)
+        return result
+    }
+}
+
+fun box(): String {
+    val v1 = ArrayWrapper<String>()
+    val v2 = ArrayWrapper<String>()
+    v1.add("foo")
+    v2.add("bar")
+    val v3 = v1 + v2
+    return if (v3.contents.size() == 2) "OK" else "fail"
+}