Add Nodejs 6/7 support

Author: syndbg

README.md

@@ -1,4 +1,4 @@
-Node v4.x.x/5.x.x Now Supported
+Node v6.x.x/7.x.x Now Supported
 ---------------------------
 
 Many thanks to [Mário Freitas/imkira](https://github.com/imkira) for his work.
@@ -15,7 +15,9 @@ Works/worked with NodeJS versions:
 * 0.8.x,
 * 0.10.x,
 * 4.x.x,
-* 5.x.x
+* 5.x.x,
+* 6.x.x,
+* 7.x.x
 
 To install, just type:
 

package.json

@@ -17,6 +17,6 @@
     "test": "node test/unittest.js"
   },
   "dependencies": {
-    "nan": "~2.1.0"
+    "nan": "~2.5.1"
   }
 }

protobuf_for_node.cc

@@ -106,7 +106,7 @@ namespace protobuf_for_node {
       }
 
       Local<Object> NewObject(Local<Value> properties) const {
-        return Constructor()->NewInstance(1, &properties);
+        return Nan::NewInstance(Constructor(), 1, &properties).ToLocalChecked();
       }
 
       Type(Schema* schema, const Descriptor* descriptor, Local<Object> self)
@@ -139,7 +139,7 @@ namespace protobuf_for_node {
 
         Local<Function> constructor =
           Script::Compile(Nan::New<String>(from.str()).ToLocalChecked())->Run().As<Function>();
-        constructor->SetHiddenValue(Nan::New<String>("type").ToLocalChecked(), self);
+        Nan::SetPrivate(constructor, Nan::New<String>("type").ToLocalChecked(), self);
 
         Local<Function> bind =
           Script::Compile(Nan::New<String>(
@@ -427,7 +427,7 @@ namespace protobuf_for_node {
 
       Local<FunctionTemplate> typeTemplate = Nan::New(TypeTemplate);
       result = types_[descriptor] =
-        new Type(this, descriptor, typeTemplate->GetFunction()->NewInstance());
+        new Type(this, descriptor, Nan::NewInstance(typeTemplate->GetFunction()).ToLocalChecked());
 
       // managed schema->[type] link
       //