Fix deprecation warnings

src/Canvas.cc

@@ -353,7 +353,7 @@ NAN_METHOD(Canvas::ToBuffer) {
       return Nan::ThrowError(Canvas::Error(status));
     }
 
-    TryCatch try_catch;
+    Nan::TryCatch try_catch;
     status = canvas_write_to_png_stream(canvas->surface(), toBuffer, &closure);
 
     if (try_catch.HasCaught()) {
@@ -445,7 +445,7 @@ NAN_METHOD(Canvas::StreamPNGSync) {
   closure.compression_level = compression_level;
   closure.filter = filter;
 
-  TryCatch try_catch;
+  Nan::TryCatch try_catch;
 
   cairo_status_t status = canvas_write_to_png_stream(canvas->surface(), streamPNG, &closure);
 
@@ -564,7 +564,7 @@ NAN_METHOD(Canvas::StreamJPEGSync) {
   closure_t closure;
   closure.fn = Local<Function>::Cast(info[3]);
 
-  TryCatch try_catch;
+  Nan::TryCatch try_catch;
   write_to_jpeg_stream(canvas->surface(), info[0]->NumberValue(), info[1]->NumberValue(), info[2]->BooleanValue(), &closure);
 
   if (try_catch.HasCaught()) {

src/CanvasRenderingContext2d.cc

@@ -743,8 +743,8 @@ NAN_METHOD(Context2d::GetImageData) {
   Local<Int32> shHandle = Nan::New(sh);
   Local<Value> argv[argc] = { clampedArray, swHandle, shHandle };
 
-  Local<FunctionTemplate> cons = Nan::New(ImageData::constructor);
-  Local<Object> instance = cons->GetFunction()->NewInstance(argc, argv);
+  Local<Function> constructor = Nan::GetFunction(Nan::New(ImageData::constructor)).ToLocalChecked();
+  Local<Object> instance = Nan::NewInstance(constructor, argc, argv).ToLocalChecked();
 
   info.GetReturnValue().Set(instance);
 }