Added @NonNull on parameters feature (issue 514),

including docs and changelog.

test/transform/resource/after-ecj/NonNullOnParameter.java

@@ -0,0 +1,61 @@
+class NonNullOnParameter extends Thread {
+  NonNullOnParameter(@lombok.NonNull String arg) {
+    this(arg, "");
+    if ((arg == null))
+        {
+          throw new java.lang.NullPointerException("arg");
+        }
+  }
+  NonNullOnParameter(@lombok.NonNull String arg, @lombok.NonNull String arg2) {
+    super(arg);
+    if ((arg2 == null))
+        {
+          throw new java.lang.NullPointerException("arg2");
+        }
+    if ((arg == null))
+        throw new NullPointerException();
+  }
+  public void test2(@lombok.NonNull String arg, @lombok.NonNull String arg2, @lombok.NonNull String arg3) {
+    if ((arg == null))
+        {
+          throw new java.lang.NullPointerException("arg");
+        }
+    if ((arg3 == null))
+        {
+          throw new java.lang.NullPointerException("arg3");
+        }
+    if ((arg2 == null))
+        {
+          throw new NullPointerException("arg2");
+        }
+    if ((arg == null))
+        System.out.println("Hello");
+  }
+  public void test3(@lombok.NonNull String arg) {
+    if ((arg == null))
+        {
+          throw new java.lang.NullPointerException("arg");
+        }
+    if ((arg != null))
+        throw new IllegalStateException();
+  }
+  public void test(@lombok.NonNull String stringArg, @lombok.NonNull String arg2, @lombok.NonNull int primitiveArg) {
+    if ((stringArg == null))
+        {
+          throw new java.lang.NullPointerException("stringArg");
+        }
+    if ((arg2 == null))
+        {
+          throw new java.lang.NullPointerException("arg2");
+        }
+  }
+  public void test(@lombok.NonNull String arg) {
+    if ((arg == null))
+        {
+          throw new java.lang.NullPointerException("arg");
+        }
+    System.out.println("Hey");
+    if ((arg == null))
+        throw new NullPointerException();
+  }
+}