catch KeyboardInterrupt for dump_cnt before exit
add readme, style fix, sample update
catch json stringify error
update readme
update readme and ...

@config helper for base_handler
rowid old typo in base_handler
force_update support in BaseHandler.crawl
default orig_url, time member for Response
find the last BaseHandler not the first for project_module
using minimum version in requirements
wait for size change
inform scheduler and processor when project updated.

wait for subprocess to exit.