Implement typed_array

[Alex-PLACET]

Fix #61

[jjerphan]

Thank you, @Alex-PLACET.

Here is a first review.

[JohanMabille]

Thanks for this initial implementation. Here are a few comments, I find it easier to gather them rather than spreading them in the diff:

• Now that Layouts now store a reference to array_data instead of a value #51 is merged, the layout classes' copy and move semantics are deleted. Therefore the typed_array class should implement proper semantics.
• Nitpicking: Since the API is going to grow, it could be nice to organize the different methods in the same order as std::vector, with the same sections (element access, iterators, etc). Notice that I am following the same "convention" in the incoming refactoring of the buffer class.
• Even if the buffer and the layout classes do not provide all the required methods to implement resize/insert/erase/clear, there are a couple of methods that can already be instantiated: front / back / data / empty (and I'm probably missing some of them)
• I think comparison operators can also be implemented

[jjerphan]

A review with some outdated comments, I believe.

[jjerphan]

Definitely LGTM.

I just have one comment.

[SylvainCorlay]

Congrats on getting the PR in @Alex-PLACET !