v3.0.0

• Minimum php version is 5.6 now.
• Added support for retrieving public spreadsheets
• Added support for retrieving resources by id, improves performance
• Request class now returns the actual error message from the Google API
• Added context specific exceptions
• All classes which accept XML in the constructor are consistent now. They all take a SimpleXMLElement as the first parameter
• All XML generation code now uses SimpleXML to generate the XML, no more string concatenation. This prevents errors when using certain characters which are not valid in XML such as '&' without escaping
• Added formula support in batch requests
• SSL verification option added to DefaultServiceRequest
• 100% test code coverage