This module contains the sequence datastructure of the
TCS Alignment Toolbox. It defines the possible value sets in the
ValueType enum as well as the different KeywordSpecification classes, namely:
1.) StringKeywordSpecification for string type values.
2.) SymbolicKeywordSpecification for values from a discrete alphabet (also refer to the Alphabet class)
3.) VectorialKeywordSpecification for vectors of some length (or for scalars)
A NodeSpecification is a vector of such ...