When we skip running a frame for a MovieCilp, we skip all
of its children as well. However, this skip 'counts' as
a skip for any children that already wanted to skip their next
frame. For example, say we create three objects in ActionScript,
and arrange them like 'obj1 -> obj2 -> obj3'.
The first 'obj1.enter_frame' call will not run a new frame
for any of the objects, but next time, 'obj1.enter_frame'
will run a new frame for all of the objects.
This fixes jacksmith, which was missing a frame1-framescript
due to 'enter_frame' getting incorrectly run for a deeply
nested child.
In future versions of `gc-arena`, the `Debug` impl. of `Gc`
and `GcCell` will print the pointed-to value, which will cause
derived `Debug` impls. to enter an infinite recursion.
As such, this manually implements `Debug` on types wrapping a
`Gc/GcCell` to maintain the current behavior.
This uses a "VM tendency" system wherein the presence of `DoAction` or `DoInitAction` tags defaults the movie to AVM1, while the presence of `DoABC` defaults to AVM2. The presence of a `FileAttributes` tag allows setting the VM tendency in the same manner using it's AS3 bit.
Particularly malformed SWFs may cause execution issues if Flash Player uses a dramatically different system from this.
This requires the use of an intermediary enum called `AvmObject` which can hold either object representation. Currently, it's mostly just being unwrapped as AVM1 objects, which we will need to fix.