returned by some controller methods.

With this changeset the spring servlet configuration is separeted from the
application configuration. This will result in a main context and a servlet
context, holding only spring mvc information.

This change has a very nice side effekt: Spring AOP beans will be loaded
only once in application context, not a second time in mvc servlet context.

This is a quick fix for HTTP session timeout which will result in some
strange behavior in client devices.

THIS MUST BE REVOVED if client JS code is able to re-authenticate from
local storage after session timeout.

This checks if there is a user in current security context. If not, an
UnauthorizedException is thrown which will result in HTTP - 401.

* @ResponseBody Annotation for JSON Response
* Old ARSnova Servlet does nothing
* New Spring Servlet loads Beans, Services, Security and SocketServer
* One Property Loader which is used in XML Spring Configuration and with
@Value Annotation

With this configuration both
 - spring security setup
 - bean properties
will be set to values defined in /etc/arsnova/arsnova.properties.

Admins ARE REQUIERED to create production settings file by given example
in /etc/arsnova.

This MUST be done because local developer settings ARE different to
the given example settings.

Deployed settings MUST be prepared by build process to match production
environment.

DO NOT expect local example settings will match all production settings.

user gets back to the right arsnova

This reverts commit 04bd8274.

* If a user posts new feedback, while having already posted one, the value
gets updated. This prevents feedback adding up.
* If feedback is too old (10 minutes), it gets removed. For testing
purposes the cleaning routine currently runs every few seconds, and
feedback only lasts a few seconds as well.
* The deleted feedback changes are broadcasted to:
	o All users, if feedback of other users has been deleted.
	o The user whose feedback got deleted.

Currently, this is a huge mess! There are three types of "Session Ids":
* The Socket.IO "session"
* The internal CouchDB session id
* The ARSnova session keyword

A severe clean up is needed before proceeding any further...

properties loaded from local filesystem

remove websocketcontroller and let sessioncontroller do the
authorization
add toString to User entity

in session stored referer

Properties from properties file are available in all beans now.
CouchDB connection in SessionService will be created using these settings.
If a connection fails, the next request will have a new try instead of
throwing an exception.

switch to oauth2 authentication which allows facebook, twitter, google
etc authentication

redirection

include config.properties.example and let override values by
config.properties
cas spring security configuration adjustments 

* Added session controller with method to get session by id
* Created session class to be used as entity object
* Created session service class and interface
* Added content negotiation view resolver to map entity objects to JSON