Allow disable of cookie check in session handle
Add system test for session handling
Add system test for content list handling
Bugfix issueContent operation
Initial work on PHP test client
Return null on SoapFault

Store last fault type and message in class. Add class methods for
retrieving fault type and message. Also add method for checking if last
operation failed.
Add PHP test client
Merge pull request #6 from kolibre/system-testing

System testing