rot13: adding some tests.
rot13: adding some tests.

sarvex/factor-lang,slavapestov/factor,factor/factor,bpollack/factor,AlexIljin/factor,bjourne/factor,AlexIljin/factor,bpollack/factor,slavapestov/factor,slavapestov/factor,tgunr/factor,sarvex/factor-lang,factor/factor,sarvex/factor-lang,slavapestov/factor,dch/factor,AlexIljin/factor,dch/factor,sarvex/factor-lang,dch/factor,nicolas-p/factor,mrjbq7/factor,mrjbq7/factor,bpollack/factor,AlexIljin/factor,tgunr/factor,factor/factor,nicolas-p/factor,dch/factor,AlexIljin/factor,tgunr/factor,bjourne/factor,AlexIljin/factor,factor/factor,nicolas-p/factor,nicolas-p/factor,nicolas-p/factor,bpollack/factor,sarvex/factor-lang,mrjbq7/factor,tgunr/factor,mrjbq7/factor,mrjbq7/factor,nicolas-p/factor,slavapestov/factor,bpollack/factor,sarvex/factor-lang,sarvex/factor-lang,tgunr/factor,factor/factor,bpollack/factor,bjourne/factor,factor/factor,slavapestov/factor,bjourne/factor,AlexIljin/factor,dch/factor,dch/factor,bpollack/factor,bjourne/factor,bjourne/factor,slavapestov/factor,bjourne/factor,mrjbq7/factor,tgunr/factor,nicolas-p/factor