Provide Intelligent Strategy-based Routing

[embario]

It may be beneficial to define strategies for having the framework choose an appropriate task for the incoming request, instead of the request choosing the task.

This might be solved by inheriting the AbstractWorkFlow class and defining an input strategy to determine which task is chosen. This would also require changes to the route() call, which should also overload its signature to treat Tasks and WorkFlows as optional parameters. This would give flexibility to the CrowdRouter manager to define the same strategies at a higher level as well, not just within one WorkFlow for choosing which task to perform.