Convert the codebase to Objective-C++ (#1206)

* Convert the codebase to Objective-C++ throughout. One language is better than two.

* Put it back

* Fix linker

* Point explicitly to updated Weaver to unblock build

* Revert "Point explicitly to updated Weaver to unblock build"

This reverts commit fdc25296e8794d4e6e56c35f5fe6da2be3f71dbc.

* Revert "Fix linker"

This reverts commit 7be25f91519b8497ef42de79f115bcfbdb965c39.

* Add in the frameworks

* no message

* Address spec lint warnings

* Fix tvos build

* Put that back

* Address Michael's review

* Add comment to kick CI

Source/TextKit/ASTextKitEntityAttribute.mm

@@ -0,0 +1,39 @@
+//
+//  ASTextKitEntityAttribute.mm
+//  Texture
+//
+//  Copyright (c) Facebook, Inc. and its affiliates.  All rights reserved.
+//  Changes after 4/13/2017 are: Copyright (c) Pinterest, Inc.  All rights reserved.
+//  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <AsyncDisplayKit/ASTextKitEntityAttribute.h>
+
+@implementation ASTextKitEntityAttribute
+
+- (instancetype)initWithEntity:(id<NSObject>)entity
+{
+  if (self = [super init]) {
+    _entity = entity;
+  }
+  return self;
+}
+
+- (NSUInteger)hash
+{
+  return [_entity hash];
+}
+
+- (BOOL)isEqual:(id)object
+{
+  if (self == object) {
+    return YES;
+  }
+  if (![object isKindOfClass:[self class]]) {
+    return NO;
+  }
+  ASTextKitEntityAttribute *other = (ASTextKitEntityAttribute *)object;
+  return _entity == other.entity || [_entity isEqual:other.entity];
+}
+
+@end