Added regression tests for all surrogate models provided by `surrogate.simple` and `surrogate.smile`. Fixed minor bugs that prevented regression tests to work.

Closes #84
Resolve "Create regression tests for surrogate functions"

Moved up name attribute to Definition to allow creation of PropertiesSpecifications independent of the fact we are using Data or a Type. #54

[WIP] Half-way of making the Genotype configurable. Restructuring to remove hard dependency to vector-based genotype. #54

Introduced base::Definition to have a common ancestor for TypeDefinition and DataDescription. This is necessary to better implement #53 in EvoAl.

Besides of declaring the possibility of 'data or type of instance', we have to introduce a new rule for adding a type definition reference. Therefore, we introduced a InstanceDefinitionReferenceRule. #53