Purpose of Colony modelling

[bevans2000]

@mokun I've come across a serious bug in the Colony modelling. But I'm puzzled why we have not seen this before as the code does not look new. The scenario is:

1. A Colonist is removed from a Population because there is a lack of Research projects
2. The Colonist is placed back on the Nation pool and detached from the Colony
3. In the future, research projects increase and the Colonist is retrieved from the Nation pool and added back to the Population
4. But it is not attached to the Colony, i.e. setColony method. On the next time pulse a NPE is thrown because the Colonist has no Colony

This has always been present so I believe the recent changes to the Reporting Authority has in some way made the Colony modelling start creating research projects. However when looking through the code is seem very "fresh", for example it specialises a Colonist to Researcher or Specialist but holds them in a single list; when drawing them out there is a potential for a ClassCast exception.

It's not visible to the end user either as there is no UI presence so it's just a bunch of log messages in the background consuming cycles.

So as well as fixing the NPE I'm going to add something to the Scenario that defines how many Colonies are created allowing us to set it to zero by default. When we develop it more we can change the default colony number.