Changes

|Feature stage=DraftDefinition

* it would open up the possibility of adding graphical addon development interfaces (like those in the original prototype, in Builder, and in Alexandre Poirot's port of the SDK's functionality to an addon) to Firefox itself * it is a step towards merging the SDK and Builder into one product - this product could also be an open web app* makes it easier for us to achieve "test without restart" which is already on the roadmap* Removes the dependency of Python which is a stumbling block to Windows users* Using the SDK to actually build itself (a complicated add-on) shows our confidence in the system to create a complex add-on|Feature users and use cases=The target audience is addon developers. The use case is an add-on developer using the Add-on SDK (either directly or via the Add-on Builder) to build an addon.|Feature implementation notes=The current plan includes a good deal of investigative work. We need to make sure that the needs of the Builder (time consuming processes) cannot be solved in other ways that might reduce their priority on this work. We also need to investigate what it would take to achieve parity with what we currently ship. This work brings along the possibility of having to maintain two different code paths which we do not want to do. It may be possible to take a small portion of the work, in the form of providing the functionality of ''cfx run'' and integrate that with the Builder. This also presents dual code path maintenance but is far less of a worry than trying to replicate more of the platform.