Add reading initial save attributes based on constants

[gutnar]

I am working on an application that reads the save file as soon as it is created. I have added an example of such a file as examples/chars/98/InitialSave.d2s.

The initial save does not seem to contain readable data for the attributes, items and skills. To resolve this I made the following changes:

• extended the parser for constants to also read the starting attributes for the classes
• when the attributes header is not found and the character level is 1 then the attributes are calculated based on constants
• when the items header is not found and the character level is 1 then no items are returned
• when the skills header is not found and the character level is 1 then no skills are returned

This could still be improved by:

• returning starter items based on class
• returning starter skills based on class