Merge pull request #18 from zillabyte/xiao/master

@sjarvie, @jakequist, @benjaminchan -- fix zb local so multiple downstream operations can consume the same str
better error handling
Merge branch 'master' of github.com:zillabyte/motherbrain into jake/master
Merge pull request #19 from zillabyte/jake/master

@sjarvie -- fix some issues affecting the web-crawlers perf