write a bunch of unit tests for the desired javascript inheritance api
and of course, instanceof should work as you expect
sketch extend method
can extend, construct, and delete
instanceof passes
properties set in constructor persist to methods
A bunch of other tests pass now too.
concrete methods are accessible externally.  also rethink some other tests.
make optional methods work
pass jshint
some notes for future functionality.
demonstrate how binding optionally-overridden virtual functions can work.
Remove .implement from the public API
give a good error message when a pure virtual function is not implemented in JavaScript
Support deriving from abstract classes with constructors
checkpoint returning JS instances out of embind
Rename initialize to __construct to avoid conflicting with C++ function names
Call __destruct on the JS implementation when the instance is destroyed.
If embind knows about a live JavaScript instance and it matches a raw pointer that gets returned, then return the JS instance.
handle some scenarios where you mix delete() and deleteLater()