class LoadDialog:
- chain code and model serial is implemented as combo box

class *Model:
- separated constructing the objects and loading the structures from the sources
- getChains() and getModels() determine all present chain codes and model serials in the sources

class View:
- adapted new loading scheme for the models
- implemented chain code and model serial Getters for the retrieval of all present chain codes and model serials in the source

class SADPDialog:
- some changes in function main(...) due to the new loading scheme for models

class Start:
- some changes in function preloadModel(...) due to the new loading scheme for models
- changed default settings for the contact type and the contact distance according to Michael's suggestions