Allow aggregate initialisation of components?

https://github.com/alecthomas/entityx/blob/6389b1f91598c99d85e56356fb57d9f4683071d8/entityx/Entity.h#L648

Seems like the line I've tagged could be easily changed to use brace initialisation rather than direct initialisation. I'm wondering if this has been considered previously and any reason for the choice to avoid it.

Brace initialisation would allow for [aggregate initialisation](https://en.cppreference.com/w/cpp/language/aggregate_initialization) meaning that you don't need to manually create a constructor for each component. Given that components should frequently qualify as aggregates this would seem to be a nice improvement by removing the need to create constructors unnecessarily.

Thoughts?