Objects should get the GlobalObject from themselves instead. However,
it's not yet available during construction so this only switches code
that happens after construction.
To support multiple global objects, Interpreter needs to stop holding
on to "the" global object and let each object graph own their global.
This adds regex parsing/lexing, as well as a relatively empty
RegExpObject. The purpose of this patch is to allow the engine to not
get hung up on parsing regexes. This will aid in finding new syntax
errors (say, from google or twitter) without having to replace all of
their regexes first!
