major change

AST nodes require range property!!!, this means if you are using the API and have it deobfuscate AST you must have your parser emit range property on each node

remove dead variables (not read/wrote anywhere)
replace variables that are only read in functions (fixes terser's object unpacking to variable)
unpack arrays that start with a "null" element
demangle minified functions so that they match stringdecoder's required schemas