#160 Patch needs completion: Multiple key in sd fields

[Stefan Kuhn]

The iteratingmdlreader now reads multiple fields with the same key into a list. Until now, values were overwritten. The specification does not say if it is allowed or not to have this, but in practice it exists

[Stefan Kuhn]

[Egon Willighagen]

I have consulted people about multiple fields, and it is indeed allowed.

About the patch, I would like to ask you to:

• describe the functionality in the JavaDoc of the class
• write a unit test
• implement this for the non-iterating SDFReader too, so that they remain consistent
• elaborate on how you envision List<>'s get written by the MDL writers: as one field, or as multiple fields
• preferable implement the writing too
• update the copyright header to list your 2010 copyright part

[Egon Willighagen]

This patch is unfinished, but already reviewed.