[BUGFIX release] Ensure exports are setup for node build.
[Bugfix beta] ensure pushUnique targetQueue is cleared by flush
Merge pull request #5490 from stefanpenner/fix-bb

[Bugfix beta] ensure pushUnique targetQueue is cleared by flush
remove unused vars and enforce in jshint
Merge pull request #5475 from emberjs/unused-jshint-vars

remove unused vars and enforce in jshint
Merge pull request #5489 from rwjblue/ensure-exports-for-nodeland

[BUGFIX release] Ensure exports are setup for node build.
[BUGFIX beta] instrument should still call block even if no subscribers
Pass depKey and old/new value to will/didChange

Until now, when a property is set, we were passing to [did|will]Change
only the object and the name of the property.
This information is very limited for some uses.
I can be very handy by example to know inside didChange the old value of
the property.
Similarly, it can also be useful to know the new value inside willChange
When the didChange is triggered by changes in a dependency, we might also
need to know which dependency changed.

All this information was available in the `set` method, so now those
values are propagated all the way thought `iterDeps` until didWill change.
I've figured out a hacky way of testing this.
Added a test for changes in non-trackeable arrays

p.e. `myArray.[]`
Pass the change info until didChange/willChange...

...also for array dependencies.
In this kind of changes, the only information I have is the numbed of values
added, but not the actual elements being added.