This also rearranges some things about how we construct events, because `MouseEvent` has different defaults from `Event`. When we finally support parameter metadata on methods we should remove that code.
We also remove the `value_of` code on `EventObject` as that was a mistake. Events don't do anything special in there and I misinterpreted the test results the first time around.
This requires adding another notion of mouse-release events to `ClipEvent`. We now have four:
* `MouseUp` - the mouse was released, any object on the render list can handle this event ("anycast" event)
* `MouseUpInside` - the mouse was released inside this display object, only the mouse-picked target of the event can handle it
* `Release` - the mouse was released inside the last clicked display object
* `ReleaseOutside` - the mouse was released outside the last clicked display object
For those keeping score at home, in AVM2, the valid progression of events is either...
* On the same object, `mouseDown`, `mouseUp`, and `click`
* On one object, `mouseDown`, then some mouse movement that takes the cursor out of the first object, then on another object `mouseUp`, and then finally the first object gets `releaseOutside`.
`MouseDown`/`MouseUp` are effectively broadcasts; they hit every movie clip that can accept them until one of them has a handler for it. AVM2 instead wants events that only apply to specific mouse-picked display objects, which means we need to use the Player-tracked events `Press`, `Release`, and `ReleaseOutside`. The only problem is that we also need to emit a `mouseUp` event on both `Release` and `ReleaseOutside`.
SWFv5 always calls `Object.valueOf` at least once and sometimes
twice in the Equals2 op, even when comparing two Objects.
For example, `Object(1) == Object(1)` is true in SWFv5 but false
in SWFv6.
Consolidate several cases and fix some issues:
* Object-to-primitive comparison always goes through `valueOf`.
* `Object(undefined) == undefined` is true; this will coerce
to a bare object with no `valueOf`, resulting in
`undefined==undefined`.
* `{valueOf:function() { return NaN; }} == NaN` is true.
When creating a scope for a closure, any `with` scopes were being
filtered out, but this was incorrect; `with` scopes are still on
the scope chain when the function is called.
Flash ignores mismatched end tags (i.e. end tags with a missing/different
corresponding start tag). `quick-xml` checks end tag mismatches by
default, but it cannot recover after encountering one.
Commit 7e20543578 already disabled
`quick-xml`'s check, but that caused mismatched `Event::End` to be
handled, which may empty `format_stack` and later panic on
`format_stack.last().unwrap()`.
Thus, check for mismatched end tags ourselves, in a similar manner
of `quick-xml`, but in a recoverable way.
* Have `DefineFunction` and `DefineFunction2` go through the same
code path by implementing `From<DefineFunction>` for
`DefineFunction2`.
* Change `register` to a `Option<NonZeroU8>` for size optimization.
* Add `function::Param` to store param info instead of a tuple.
David Wendt