Fixed problem with service() call

[shockflash]

It seems that OpenInventor changed the webservice for the services.php. Updated the code to handle the incomming serialized php array, used the external module "phpserialize", which is now also a dependency.

It contains also a small fix, the _request() now uses the parameter "path" instead of the variable self.api_path

Update: Now some fixes for the forms are added, too. Also a new testapp is available to make the first steps with DjangoOpenInviter a little bit easier.

I also removed the outdated OpenInviter source code, especially since there now is a repo with the OpenInviter source in my account available: https://github.com/shockflash/OpenInviter