Allow us to choose what to test because timeout tests and job management
tests take too much time.

query.exec([{"title": "hello"}, null], {"select_list": "title"});
// before: TypeError: list[i] is null
// after: [{"title": "hello"}]

Job queues are now saved in workspace at different moment

Test if an object is a native object (`var object = {};`) seams not to be a good
idea. The Firefox scratchpad seams to act differently with them.

http://semver.org

davstorage.tests.js is hybrid, you can use it with real server or fake server.

To avoid sinon bug: fake server responds twice