Bug: vector swap overload resolution

[bivafra]

Problem

swap in the Vector is defined inside the class as a friend function. This enables ADL, that is, the function will be found through the unqualified swap(a, b) call. However, for the qualified call bmb::swap(a, b) the compiler will use general swap definition through moves.

Possible solution

Declare swap as a template friend function inside the Vector, then define it after the class definition. After that, the compiler will always choose proper swap version for both qualified and unqualified calls.