updated book status to RESTful, PUT and AJAX

changes in __init__.py:
- removed, change_status_book route no longer needed, RESTful requests
take care of which view will respond;

- changes in library template:
- - - added jquery and library.js;
- - - other changes and fixes.

changes in LibraryView.py:
- updated changes_status_book view:
- - - now its named book_status;
- - - now it responds to restful PUT requests that containt
request_parameter (action=change_status);
- - - minimal changes in method itself;
- - - return of this view is True on success, and False on failure
- - - js responds to returns appropriately