Encode params if sent as body

Encoding parameters when sending them in body leads to incorrect parsing of the server. If the form is sent as a multipart the parameters do not need to encode. When parameters are passed through the form (iframe), take care of this browser. Sorry for my english.

Improved qq.obj2FormData method. 

* Added support for Array
* Boolean values ​​are replaced by 1 or 0
* NULL values ​​are replaced with an empty string
* Consider the case when the parameter is a function and returns an Object or Array