From all I can know, it's impossible, because AGK::agk is a class.
AGK is namespace and it's member agk is a class.
If agk was an namespace nested inside AppGameKit, then you could do that:
namespace app_game_kit = AGK::agk;
using namespace app_game_kit;
And all would work, but since it's a class, you'd have to:
using AGK::agk::LoadImage(...);
using AGK::agk::DeleteImage(...);
using AGK::agk::CreateSprite(...);
using AGK::agk::DeleteSprite(...);
...
And so on, for all AGK's functions nested inside agk class.
