* Let users specify tasks directly under a Locust class, just as one would do it on a TaskSet class. These tasks will get the Locust instance as argument when executed.
* Removed Locust.task_set from the public API, and instead let users use either the tasks attribute or the @task decorator.
* Introduce a Locust.abstract boolean attribute. If it's set to True the Locust class is meant to be used as a base class, and users of that type can not be spawned directly from it.

…der Locust classes.

Some general documentation improvements here and there.

…d coding DefaultTaskSet as far as I can tell

… type TaskSet (that hasn't been decorated by @task)