fixing bug #5953
fixing bug #5997 infoletter

Conflicts:
	infoletter/infoletter-jar/src/main/java/com/stratelia/silverpeas/infoLetter/implementation/InfoLetterDataManager.java
	infoletter/infoletter-war/src/main/java/com/stratelia/silverpeas/infoLetter/control/InfoLetterSessionController.java
Bug #5997: fixing some problems
- refactoring the code
- using centralized treatments around WYSISYG (WysiwygController)
- using the new transformer class for WYSISYG

Conflicts:
	infoletter/infoletter-jar/src/main/java/com/stratelia/silverpeas/infoLetter/implementation/InfoLetterDataManager.java