Add in support for route variables

[mscosti]

Similar to flask and other web app frameworks, this adds support for adding in generic variables in your route definitions. On incoming HTTP request, if a path matches a route template that has some variables in it, it will parse out those variables, and then pass them along to the request handler as arguments to the function.

example:

@app.route('/customer/<id>')
def getCustomer(environ, id):
    ...

important to note: If you have multiple variables in your path, then the order that your function receives those variables is the order in which they are defined in the route template.