Defer I/O for package requires until they're actually used

[nathansobo]

This is an experiment that uses some harmony proxy magic to defer all require I/O until the moment the required modules are actually used. Harmony proxies have some instability when combined with so-called "irregular objects" such as arrays and Date objects, but 99% of the time the objects returned by require are not irregular. If it ends up being stable it may be worth it because it cuts our load time without bothering users much.

[nathansobo]

I just noticed it seems increase activation time. So this will need further investigation tomorrow. The good news is it might obviate the need for the deferral events because the actual use of objects won't happen until the events happen anyway, allowing for more natural registration.

[kevinsawicki]

Would you be cool maintaining the sorted order of dependencies for readability?

[nathansobo]

Definitely. I think I just used npm install --save which tacks stuff on to the end. I'll re-order.

[nathansobo]

This is turning out to be too complicated for now I think. I may want to revisit it and try again later, but I'm worried it's taking too much time.