Rattlepy

* added: HTML node placeholdering.

* changed: createHeader function argument.
* fixed: scaffold function.
* fixed: exposes function on Element object.
* fixed: element formatters recursive reference bug.

* fixed: many known bugs.

* changed: text function will escape dangerous characters.
* added: rtext function.
* changed: now you can select HTML renderer.

* fixed: setup.py

* others: update docstrings and create document.