Updates Handlebars {{pluralize}} helper

Takes up to two arguments, the count and the word
e.g. {{pluralise 2 “ox”}} #=> “2 oxen”

Still allows pluralising without a count as well
e.g. {{pluralise “ox”}} #=> “oxen”
Merge pull request #43 from bradleypriest/pluralize-hbs

Replace Handlebars pluralize helpers