Add generic CSV export translator

For some tasks in my work with books I had to search for some literature and save some rudimentary bibliographic facts about each of them in a list (to work further). Moreover, I have read somewhere in the forum, that the "wish" for a CSV translator exists or take a look at http://belencruz.com/2014/03/how-to-export-from-zotero-to-excel/ or http://royce.kimmons.me/tutorials/zotero_to_excel . I think that nowadays it is more important to search and analyse larger parts of data easily, maybe also for bibliographic data. 

Here is a CSV export translator. The approach is to export all data, i.e. data fields from specific types are for the other rows empty. Moreover, the multiple fields and nested fields are translated as "paths" and can optionally also added appropriate.

Please let me know what you think.
It may be nice if the user can change this, but I think that most users will not need to. I wouldn't mind leaving this, except that according to CSV spec ([RFC4180 section 2](http://tools.ietf.org/html/rfc4180#section-2)), if a field is enclosed in double quotes and it contains a double quote, the double quote in the field needs to be escaped by placing another double quote before it (essentially `"foo ""bar"""` means `foo "bar"`). We need to make sure we perform this escape, but we can only do it if we follow the spec, which requires that fields are wrapped in double quotes.

(btw, it should be spelled "delimiter")