Consolidated _any_key_press

For issue #295

The issue occurred because:
After _any_key_press was correctly set to true on a hat event, it was often being reverted to false by the logic in _JoystickEventHandler during the event-handling loop. Since _any_key_press is only assigned in the event handling loop, and not evaluated, it makes more sense to assign it once after all events have been handled.

I tested this change in all menus that use InputEngine::AnyKeyPress(), using the keyboard, and Xbox 360 controller joysticks and D-pad. All seem to work as expected.