added missingParser error message as a variable, to save repetition
added missingParser error message as a variable, to save repetition

magicdawn/ractive,cgvarela/ractive,thomsbg/ractive,ractivejs/ractive,heavyk/ractive,squaredup/ractive,npmcomponent/RactiveJS-Ractive,JonDum/ractive,marcalexiei/ractive,ndimas/ractive,magicdawn/ractive,magicdawn/ractive,p0lax/ractive,thomsbg/ractive,ndimas/ractive,ractivejs/ractive,pingjiang/ractive,cgvarela/ractive,JonDum/ractive,dyx/ractive,thomsbg/ractive,heavyk/ractive,dyx/ractive,cgvarela/ractive,ndimas/ractive,Rich-Harris/ractive,ISNIT0/ractive,JonDum/ractive,Rich-Harris/ractive,squaredup/ractive,ISNIT0/ractive,aliprogrammer69/ractive,dyx/ractive,npmcomponent/RactiveJS-Ractive,aliprogrammer69/ractive,aliprogrammer69/ractive,marcalexiei/ractive,pingjiang/ractive,squaredup/ractive,pingjiang/ractive,ractivejs/ractive,heavyk/ractive,p0lax/ractive,marcalexiei/ractive,ISNIT0/ractive,Rich-Harris/ractive