start to develop packing phase.

- finishing coping necessary files to `dist/`.
compressing css files using csso.
display packed css files size.
use gulp-filer to refactory gulp task pack:js.
use gulp-filter to refactory gulp task pack:html.
gulp task pack:css - remove unneed indent.
if user using anguarljs, annotate before uglifying.
make pack:js more faster.