Generic task resource to support all types

[Mat-Co]

Previous task resource permitted only script tasks. Make the resource more generic so any kind of task can be created.

Usage examples can be found in api_examples/task.rb.

Since there is a lot of task types, i didn't created a chef resource for each one. Instead, you need to pass the task's typeId and other properties in a hash with specific keys, according to the desired task.

[jeremy-clerc]

This looks ok to me, but as I have added two commits, letting someone else approving.