OffsetOf: use of static_cast
Updatable: API and virtual destructor
Drawable: virtual destructor
Vector: std::abs should be "the" abs.
AbstractClass: API
+Updatable: Like for others abstracts
Buffer: nullptr for pointer to function.
Image: wasn't returning a vector.
Former-commit-id: 57e0009286a02b9e3b0b81945e500d7d9e466ae2