Tango events generator

Create a tango test device that generates mock events. This should be similar to the standard test device except that the device is configured (by means of a command with a spec parameter) to generate a specific set of events according to a specific set of rules. The most important event is to assist with the use case of diagnosing possible causes for the technical debt about missing tango events (see SP1091). It may however also be useful to allow the device to be configured to :

1. create a specific exception
2. respond to a command at a predefined latency (with a predetermined message)

As a possible "nice-to-have", the device can be configured to deliver a predefined storyline of events for multiple attributes in a predefined order.  The deliverable should also come with some documentation and example of a client making use of the device with some useful strategies for how to patch it during tests.