Store request parameters so they can be accessed

* Add listener to 'data' event
* Handle request on request 'end' event
Fix scope inside new book model callback
Allow new books to be added in MongoDB on post to /books

* MongoDB doesn't have incremental sequences due to it's distributed nature, store sequence in "counters" document
* Find next sequence and increment it manually before inserting new book to the Database
* Force new integer id for new book in order to keep Backbone working properly and keep books/integer URL
* Return new book :)
Add Steps to set up environment and put app up and running