Add exception checks for Dutch nouns

[agnieszkaszuba]

We need to create the forms (plurals and diminutives) of Dutch nouns that do not follow the rules for creating noun forms implemented in #356 . For example, nouns that can take more than one plural or diminutive suffix (e.g., pastor takes the plural suffix -s according to the rule, but the form pastores is also possible) or nouns that take a special suffix that is not included in the rules (e.g., kind -> kinderen).