add `fill` & `html` like `casper` & add local test server

1.Fills the fields of a form with given values and optionally submits it. Fields are referenced by their name attribute.

`//TODO: support select/checkbox/radio/file, single/multiple`

2.Provide `html(selector, parent, callback)`

3.Add local test server - use express as a devDependencies, so tests will be maintainability && run fast.

BTW, github is strange, I only pull request the first commit, then push other to my fork,  but it auto change this pull request with all commits.

Signed-off-by: TZ <atian25@qq.com>