Logger log4j
Merge branch 'BottomUp_Pocreau' of https://github.com/BeyondTheClouds/PlacementOptimizer into BottomUp_Pocreau

Conflicts:
	.classpath
	src/gipad/plan/choco/SimpleReconfigurationProblem.java
Logger fix

to use the logger :
logger.debug("msg de debogage");
logger.info("msg d'information");
logger.warn("msg d'avertissement");
logger.error("msg d'erreur");
logger.fatal("msg d'erreur fatale");