Merge pull request #27 from eike-welk/master

Installation with **pip** now possible.
New example value for `compatibility_level`

`compatibility_level = 863` really causes warnings in the 
shopping API. New value `compatibility_level = 853` works fine. 

Version 835 is also mentioned in trading API documentation as released at 2013-Dec-31. See:

http://developer.ebay.com/devzone/xml/docs/releasenotes.html
Merge https://github.com/roopeshvaddepally/python-ebay

Conflicts:
	ebay/config.ini.example