This patch adds the concept of variable bindings to the various
environment record classes. The bindings are not yet hooked up to
anything, this is just fleshing out all the operations.
Most of this is following the spec exactly, but in a few cases we are
missing the requisite abstract operations to do the exact right thing.
I've added FIXME's in those cases where I noticed it.
This was accidentally deleting a property from the object record object
itself, rather than from the object record.
It's quite confusing that Environment Records are objects, but moving
away from that will require some large changes.
These represent the outermost scope in the environment record
hierarchy. The spec says they should be a "composite" of two things:
- An ObjectEnvironmentRecord wrapping the global object
- A DeclarativeEnvironmentRecord for other declarations
It's not yet clear to me how this should work, so this patch only
implements the first part, an object record wrapping the global object.
