Added option for left & right delimiters
Added option for left & right delimiters

To prevent from “{{“, “}}” clashes between go’s template and
others(handlebars, angularjs also uses them).

cgideon/martini-contrib,Boomerangz/martini-contrib,codegangsta/martini-contrib,cgideon/martini-contrib,Boomerangz/martini-contrib