errors: remove uncaughtException handler on throw

asyncCatcher is installed to deal with synchronous throws while the
error handler is installed, and will prevent Node from appropriately
handling rethrows from asyncListener if it's active. Fixing this also
requires having an unwrapped version of process.nextTick available so
you don't inadvertently create new async events while handling errors
for previous ones. This all looks much more rickety than it feels in
practice, I promise.
deps: explicitly version lock on shimmer 1.0.0
release: 0.4.5 - correct async error handling