fixing bug #5885
IM sent messages are no more saved

Conflicts:
	lib-core/src/main/java/com/stratelia/silverpeas/notificationManager/NotificationSender.java
fixing bug #5911
storing HttpSession instead of MainSessionController...

Conflicts:
	web-core/src/main/java/com/silverpeas/look/LookSilverpeasV5Helper.java
Some corrections :
- fixing bad behavior of user authentication verifiers when the user is anonymous
- fixing the security token renew process which was not performed at right time

Conflicts:
	lib-core/src/main/java/org/silverpeas/authentication/verifier/UserMustAcceptTermsOfServiceVerifier.java