Add reverse url support to Joosy.Router

Hi,

I've added reverse url support to Joosy.Router. For this, I created a new method named draw, which works similar to one in Ruby on Rails, with a nice DSL. Example code:

```coffeescript
Joosy.Router.draw ->
  @root to: Dashboard.IndexPage
  @not_found to: -> alert("Not found")
        
  @match '/activities', to: Activities.IndexPage, as: "activities"
  @match '/feed', to: Feed.FeedPage
  
  @namespace '/projects', as: "projects", ->
    @match "/", to: Projects.IndexPage, as: "index"
    @namespace "/:id", ->
      @match "/", to: Projects.ShowPage, as: "show"
      @match "/edit", to: Projects.EditPage, as: "edit"
      @match "/delete", to: Projects.DeletePage, as: "delete"
          
  @namespace '/tickets', ->
    @match "/", to: Tickets.IndexPage, as: "tickets_index"
```

Now it's easy to get reverse url for this:

```coffeescript
root_path() # #!/
activities_path # #!/activities
projects_index_path # #!/projects/
projects_edit_path # #!/projects/:id/edit

root_url() # http://example.com/current/path/#!/
activities_url() # http://example.com/current/path/#!/activities
```