Completed and corrected Dutch translation

A. General Composure: completed the translations
B. website behavior: translated everything
D. Server behavior: completed the translations and corrected some grammer mistakes
E. general gameplay: corrected some grammer mistakes and completed the translation
F. Client Modifications: corrected some mistakes
I. Consequences: translated the title and some text + corrected a grammer mistake
contribute should be translated as bijdragen. bijbrengen is more person to person, in a way of teaching someone