Code formating and ordering

* The source file will keep and order of methods. The order will be as
following:
  1. Private functions will go first.
  2. class_init and init will go second.
  3. vfuncs implementations will go third.
  4. Public API will go fourth

* Methods naming will be according to:
  1. Private methods will have no prefix
  2. vfuncs and public API will have the right prefix

* The methods prototype will always be placed at the top of the source.