Moved default factories. Implementing persistence on bids.
Merge branch 'master' of ssh://git@github.com/Nic0w/OOAP_eBayLike_4A.git

Conflicts:
	src/main/java/fr/esiea/ooa/ebaylike/BidPlatform.java
	src/main/java/fr/esiea/ooa/ebaylike/api/PersistentBid.java
	src/main/java/fr/esiea/ooa/ebaylike/default_impl/DefaultBid.java
	src/main/java/fr/esiea/ooa/ebaylike/default_impl/DefaultBidFactory.java