db : add mongo support
parse_page : parse published time, required by rss item
parse_page : make return match rss2 spec
rss : add rss generatoe by PyGenRSS2
rss : fix key typo
rss : fix output encoding problem
parse : fix post title parsing, title may contain enhancement tag. need to get rid of it
parse_page : add novel title parsing
parsing : keep first and last page both
parsing : convert post time to rfc822 format
use exception to handle error
query db if item doesn't exist, update data into it
fetch new data when 1. no record in db. 2 record is too old