Added <macro name="substitute-title"> for unsigned articles

Added <macro name="substitute-title"> to cope with unsigned articles and reviews, where the name of the newspaper or periodical (=container-title) needs to stand in place of the author (see CMoS 14.207 and 14.217).
Create medienwandel-medienwechsel-medienwissen-chronos.csl
Update and rename medienwandel-medienwechsel-medienwissen-chronos.csl to nccr-mediality-chronos.csl

Change of names
Create helsinki-theology

Added a style from Helsinki University's Faculty of Theology
Shorter version of "substitute-title" macro

Now that pandoc-citeproc has been fixed (see https://github.com/jgm/pandoc-citeproc/issues/58), this shorter version of the "substitute-title" macro works in pandoc, too.
Create revista-fave-seccion-agrarias.csl
Rename revista-fave-seccion-agrarias.csl to revista-fave-seccion-ciencias-agrarias.csl
Update and rename revista-fave-seccion-ciencias-agrarias.csl to revista-fave.csl

The default locale has been changed from "es" to "es-ES", the missing accent in the title has been corrected and the filename, id and self have been shortened properly.
Renamed file and changed links.
Update and rename revista-fave.csl to revista-fave-seccion-ciencias-agrarias.csl
add DOI for ISME Journal articles, mainly for pre-print
PMC-21028 - potential fix for MLA style

PMC-21028 - squash
Add new ACS variant
Add two new ACS dependents
fix G3 style
fix Ugeskrift for Laeger
added <text macro="title"/> to "substitute-title" macro
Update deutsche-gesellschaft-fur-psychologie.csl
Update deutsche-gesellschaft-fur-psychologie.csl
Merge pull request #1084 from zuphilip/dgp-fix-et-al

Fix punctionat before et al. in deutsche-gesellschaft-fur-psychologie.csl