doc: fix typos in http.markdown

PR-URL: https://github.com/joyent/node/pull/4784
Reviewed-by: Chris Dickinson <christopher.s.dickinson@gmail.com>
Added output file option to gentest. json doc generator now accepts output file as well. json doc generator now generates index file automatically.
Now json doc generator writes index.json file.\n Renamed url.html and url.json to html and json
Fixed some typos. `writeOutputToFile` does not raise and exception anymore.
path: allow calling platform specific methods

Add path.posix and path.win32 which have the specific methods like
resolve and normalize so you can specifically normalize or resolve
based on the target platform.
path: added parse() and format() functions

The parse() function splits a path and returns an object
with the different elements. The format() function is the
reverse of this and adds an objects corresponding path
elements to make up a string. Fixes #6976.