changed method interface handling keywords
samples follow api changes
add documents
fix trivial issue to handle ioerror
clistream now moved into clitool.cli module
follow the move of 'clistream'
rewrite Functions and Streamer to reduce count of 'logging'
delete 'Functions' object to improve performance
avoid calling "strptime" and "urlparse" for performance improving
re-organize accesslog module not to call meaningless functions.
parse_arguments() accepts flag options.
Merge branch 'feature/clistream-api-change' into develop