Exporting individual params for backward compat

Upgrading to swagger 2.0, the index.js file is exporting individual param types under `exports` and not `module.exports` so they're not accessible that way anymore.

    var swagger = require('./swagger/')
    console.log(swagger); //swagger exports, params
    console.log(swagger.params); //q, query, path, etc
    console.log(swagger.queryParam); //undefined

Simple change, unit tests to demonstrate.