The goal of this change is to provide a better way of passing
per-crawl parameters. Since the browser_params dictionary is meant for
per-browser settings, adding in any additional parameters (like
logger_address) would require adding the address to all copies of the
dictionary. With manager_params, a single additional dictionary is
passed around to hold the crawl-wide configuration settings. This
includes things like the location of the crawl database and the log
file.
englehardt