more class and method signatures, use writer wrapper

(not yet complete)

own writer will be used to write both java and kotlin signatures

compiler/testData/compileJavaAgainstKotlin/class/ImplementsListString.java

@@ -0,0 +1,7 @@
+
+class PlainExtendsListString {
+    {
+        Mine mine = null;
+        java.util.List<String> list = mine;
+    }
+}