Add support for & syntax in ebnf
Add support for & syntax in ebnf

mecon/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,factor/factor,nicolas-p/factor,sarvex/factor-lang,dharmatech/factor,mcandre/factor,erg/factor,factor/factor,cataska/factor,cataska/factor,erg/factor,tgunr/factor,littledan/Factor,littledan/Factor,dharmatech/factor,ceninan/factor,sarvex/factor-lang,tgunr/factor,nicolas-p/factor,bjourne/factor,erg/factor,mecon/factor,mcandre/factor,nicolas-p/factor,AlexIljin/factor,jwmerrill/factor,jwmerrill/factor,slavapestov/factor,bjourne/factor,nicolas-p/factor,factor/factor,sarvex/factor-lang,kingcons/factor,cataska/factor,mecon/factor,littledan/Factor,dch/factor,AlexIljin/factor,nicolas-p/factor,dch/factor,bjourne/factor,ceninan/factor,slavapestov/factor,mecon/factor,littledan/Factor,bjourne/factor,factor/factor,mrjbq7/factor,Keyholder/factor,ehird/factor,dharmatech/factor,erg/factor,cataska/factor,bjourne/factor,sarvex/factor-lang,seckar/factor,mcandre/factor,mecon/factor,mrjbq7/factor,AlexIljin/factor,bpollack/factor,kingcons/factor,sarvex/factor-lang,seckar/factor,mcandre/factor,seckar/factor,kingcons/factor,nicolas-p/factor,tgunr/factor,nicolas-p/factor,mrjbq7/factor,erg/factor,ceninan/factor,ehird/factor,factor/factor,bjourne/factor,AlexIljin/factor,Keyholder/factor,mcandre/factor,mrjbq7/factor,slavapestov/factor,ceninan/factor,slavapestov/factor,Keyholder/factor,mcandre/factor,tgunr/factor,mecon/factor,bjourne/factor,erg/factor,AlexIljin/factor,slavapestov/factor,slavapestov/factor,sarvex/factor-lang,bpollack/factor,jwmerrill/factor,kingcons/factor,AlexIljin/factor,factor/factor,bpollack/factor,mecon/factor,dch/factor,bpollack/factor,bpollack/factor,dch/factor,sarvex/factor-lang,dch/factor,dch/factor,AlexIljin/factor,erg/factor,ehird/factor,mcandre/factor,mrjbq7/factor,bpollack/factor,tgunr/factor,slavapestov/factor