issue 43 fourth attempt. not fixed yet.
Merge branch 'master' of https://github.com/SRA-SiliconValley/jalangi into issue43-2
issue #43 more progress.  3d-raytracer and box2djs are failing now.
issue #43 more progress.  box2djs is failing.  Comment out RR_preG to pass all tests.
Merge branch 'master' into issue43-2

Conflicts:
	tests/unit/proto_prop_lookup.js
Merge branch 'master' into issue43-2
Merge branch 'master' into issue43-2
more progress on issue43
dead end on this branch
finally prototype chain recreation for mock objects seems to work.
Merge branch 'master' into issue43-2

Conflicts:
	scripts/units.py
	scripts/unitsv.py
prototype chain for mock objects works, but the mechanism is quite slow.
limited prototype chain support is now working
Merge branch 'master' into issue43-2
Merge branch 'issue43-2'

Tries to create the prototype chain in shadow memory during record.  This reduces the length of a recorded trace.