add ppa with newer json-c version; test gcc and clang.
add ppa with newer json-c version; test gcc and clang.

newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,x4121/newsbeuter,der-lyse/newsboat,x4121/newsbeuter,newsboat/newsboat,der-lyse/newsboat,travisred/newsbeuter,der-lyse/newsboat,travisred/newsbeuter,der-lyse/newsboat,x4121/newsbeuter,travisred/newsbeuter,travisred/newsbeuter,der-lyse/newsboat,der-lyse/newsboat,der-lyse/newsboat,x4121/newsbeuter