Fix #25 (install require name)

Hi,
Your module is great, but latest version has small issue. Two resources file:$node_binary and file:$npm_binary in init.pp manifest has require => Nodejs::Install["node-${version}"] but resource is nodejs::install { "nodejs-${version}" ("node-${version}" vs "nodejs-${version}").

Sorry for duplicate, I'm not very familiar with github pullrequests