Fixing bug in genRouteRegexp method.

Whenever a verb registered under path /, gonatra
would serve all the requests registered for some
given verb to that route.
Improving getParams function.

Before we would return a hash formed of string keys and
string array values. Now we simply return string keys
and string values to make it easier to access.
Simplifying tests.
Improving route registering API.

Instead of encapsulating the Http Request and request
params in a custom object, passing it directly to the
function. This is so that if people desire to not use
gonatra anymore they would just have to remove the
Params argument from their callbacks.
Renaming request.go to params.go
Adding support for PUT and DELETE.