Add bare bones `localExpand`

This is a simple implementation of local expansion. It currently does
not support stop lists, but fully expands the syntax given to it.
Merge branch 'pr/310' into merge_localExpand

Conflicts:
	test/test_macro_case.js
adding test for localExpand and local macros #310
backporting var transforms for master #310

redoing work done on es6-modules on
184ca297ac5b2a3f9f6a1902b661e51e604637d8
build