There is a new binding transform, `mix`, that allows for the aggregation of multiple bound properties into a single property through a given function. It is often the case that a single property depends on two or more bound properties in a complex manner that isn't handled by the current `and` and `or` transforms. To handle this situation previously, the developer would need to write the code to bind in the external property values and then make a local computed property dependent on each of these. The `mix` transform does exactly the same thing, but with less typing on the developer's part.

* Cleaned up the code and removed some memory leaks (undeclared variables).