Designed new API and simple example

[JohannesMeierSE]

• joint work of @insafuhrmann and @JohannesMeierSE
• Fulfills Chaining/Factory API for predefined kinds/types #24 and Create an easy example for the README #39
• All existing examples including OX and LOX are reworked to use the new factory API
• The factory API is provided for these types: primitive, top, bottom, function, class
• These types are not (yet) supported by the new factory API
  • multiplicity types: I am not sure, whether we really need this type, we should not advertise it for v0.1, but rework/redesign/improve it for upcoming versions
  • fixed parameter type: I am unsure at the moment, how to integrate it into the API, since each kind instance is specific for the current set of operators, e.g. there is a "Map kind" and another "List kind", which "both are FixedParameterKinds" (https://github.com/TypeFox/typir/pull/43/files#diff-06d7c3de2afd260ac79d91a52f56faacc286892f4786c7e7bfbd670494d97429R28)

[insafuhrmann]

Thanks for the great joint work session @JohannesMeierSE and for the additions and fixes afterwards. The Functions escaped the renaming from predefined to factory, otherwise everything seems fine to me.

[JohannesMeierSE]

Thanks @insafuhrmann for the great joint working session!