Update gesellschaft-fur-popularmusikforschung.csl

Now I solved the most problems, but the following 2 problems are not solved:

First: To alter „Hg. von“ into „Hg. v.“ (Under „locale“ I tried to create a new term „edited-by“, but this wasn’t useful (line 21)):

locale-edited-by.png

Second: The problem described on Nov. 04th:

R: I gave you wrong information. I want to realize the following two options (concerning bibliographic entries):

1.	Helms, Dietrich (2008). "What's the difference? Populäre Musik im System des Pop." In: PopMusicology. Perspektiven der Popmusikwissenschaft. (The latter titel is in italics!) Hg. v. Christian Bielefeldt, Udo Dahmen u. Rolf Großmann. Bielefeld: Transcript.
2.	Bielefeldt, Christian / Grossmann, Rolf / Dahmen, Udo (Hg.) (2008): PopMusicology. Perspektiven der Popmusikwissenschaft. (The latter titel is in italics!) Bielefeld: Transcript.

I have a problem with the editor names: I don't manage to divide the following two options: First: If the entry is a single book chapter or similar type, the editor names must appear after the title and in the order indicated above under (1.). Second: If the entry is the whole edited book, the editor names must appear before the title and in the order indicated above unter (2.).
Another problem is the delimiter "," in case (1.): I want to put the delimiter "u." only between the last two names. All names before must be divided with the delimiter ",".