Copy comments from a bundle list to annotation structure

[MJochim]

After defining a parallel label "metadata" on the utterance level, it should be possible to copy all coments from a bunlde list to the respective annot.json file. This is meant for comments that shall remain in the database and be queriable.

[raphywink]

Is this because you need to be able to query the meta data a.s.a.p. or are there other reasons? In 2-3 months time I should have the first version of the _meta.json parser implemented which would mean you can query them directly and/or use them as filters in the query() function...

[MJochim]

Need not be asap. I will not do this before the end of March anyway. I'd be happy to save the comments in meta.json files instead; and I might as well wait until they are ready.

This is actually related to #28. That is, it is one way to fill the _meta.json's with useful information.