better entity values comparison on save

[silentroach]

@Entity()
export class Post {
    @PrimaryGeneratedColumn()
    id: number;
    @Column({ name: "dt", type: "timestamp with time zone" })  // <-- type is important here
    date: Date;
}

const post = new Post();
post.id = 1;
post.date = new Date();
await postRepository.save(post);       // <-- first save, it is ok

const loadedPost = await postRepository.findOneOrFail(1);
await postRepository.save(loadedPost); // <-- was not changed, 
                                       // but typeorm will update the record with the same date

Entity property with column type "timestamp with time zone" value is always different for TypeORM on save.

Seems like you forget to normalize these values on value comparison function.

[pleerock]

Thanks for waiting @silentroach. I'll merge this change since Im releasing a new version today, however this functionality needs a tests, you know it =)