Fixing rabbit-trail-inducing error message
Fixing rabbit-trail-inducing error message

Added a new error message when non-string templates are passed in without a parsed-Ractive-template version.

Fixes ractivejs/ractive#1581
pingjiang/ractive,ndimas/ractive,pingjiang/ractive,magicdawn/ractive,squaredup/ractive,cgvarela/ractive,ISNIT0/ractive,Rich-Harris/ractive,heavyk/ractive,thomsbg/ractive,aliprogrammer69/ractive,Rich-Harris/ractive,marcalexiei/ractive,ISNIT0/ractive,dyx/ractive,squaredup/ractive,magicdawn/ractive,thomsbg/ractive,magicdawn/ractive,pingjiang/ractive,ndimas/ractive,thomsbg/ractive,aliprogrammer69/ractive,ISNIT0/ractive,dyx/ractive,marcalexiei/ractive,cgvarela/ractive,heavyk/ractive,marcalexiei/ractive,ractivejs/ractive,squaredup/ractive,Rich-Harris/ractive,cgvarela/ractive,ractivejs/ractive,JonDum/ractive,JonDum/ractive,JonDum/ractive,ndimas/ractive,aliprogrammer69/ractive,ractivejs/ractive,heavyk/ractive,dyx/ractive