BioAssaySetExporter breaks if names of formulas, extra values, raw data propeties not are unique

[Nicklas Nordborg]

The BioAssaySetExporter uses the name of the following items to identify things:

1. reporter properties
2. raw data properties
3. formulas
4. extra values

If more than one item has the same name the export doesn't work as expected. For example, Genepix has a raw data property 'x'. If I have a formula with the name 'x' the export will use the raw data 'x' value and not the formula.

This should be handled differently. The simple solution is to not include items with duplicate names in the list of items to select from (and maybe show a warning message that not all items can be used). A better solution would be to make sure each item can be uniquely identified. The problem is that I think the Base1PluginExecuter relies on being able to use the names to identify what to export.

[Nicklas Nordborg]

(In [3505]) Fixes #632, #622, #643, #644, #645, #646, #647