provide abbreviated api
sleep for 0.5 sec before attempting to reconnect to amqp; documentation tweaks
improve readme, mentioning archive-it per kristine
capitalize AMQP in description
add options --verbose, --exchange, --queue, --routing-key
make umbra amenable to clustering by using a pool of n browsers and removing the browser-clientId affinity (not useful currently since we start a fresh browser instance for each page browsed), and set prefetch_count=1 on amqp consumers to round-robin incoming urls among umbra instances