WIP on this lazy JSON parsing business (see #29)
JSON parsing is working well w/ everything but nested objects (see #29)
sort of have lazy JSON parsing working... ish... needs a lot more testing!
updated AsyncSequence#each so error callback doesn't get ignored on first iteration
wrapped up Lazy.parseJSON as a module-y thing

...and made some improvements along the way
created a little demo for lazy JSON parsing (see #29)
updated layout of JSON parsing demo, added cancel button (see #29)
implemented TakeIterator
added completeCallback to async handle
updated JSON parsing demo w/ little status counter (see #29)
more trivial updates
added global error handler to demo.js