pipelet.js: ...
  - set_default_options(): add defaults object to provide additional default options.
  - build() and Compose(): provide default option for name as the name of the pipelet.
  - dispatch():
    - implement performance options 'no_encapsulate', 'single', and 'input_output'
    - implement a reliable solution to get the input of branches
    - refactor to improve performance, both execution and minified code size

test/http.js:
  - socket io dispatche: use 'no_encapsulate' and 'input_output' options