OBMFULL-5353 Update a test class style
OBMFULL-5353 Upgrade ehcache version to 2.7.2
OBMFULL-5353 Add a test about restoring cache datas from disk
OBMFULL-5353 Memory space allowed to ehcache stores is now tunnable
OBMFULL-5353 Add test on overflow to disk, but ehcache always respond false to isElementInMemory
OBMFULL-5353 Introduce a time unit mapper from String to TimeUnit

Conflicts:
	java/sync/opush/push-dao/src/main/java/org/obm/push/store/ehcache/EhCacheConfigurationFileImpl.java
OBMFULL-5353 Add timeToLive in ehcache configuration file

Conflicts:
	java/sync/opush/push-dao/src/main/java/org/obm/push/store/ehcache/EhCacheConfigurationFileImpl.java
	java/sync/opush/push-dao/src/test/java/org/obm/push/store/ehcache/TestingEhCacheConfiguration.java
OBMFULL-5353 Stores must be configured with a time to live
OBMFULL-5353 New project for EhCache migration
OBMFULL-5353 Add legacy ObjectStoreManager
OBMFULL-5353 Add legacy SyncKeysDaoEhcache implementation
OBMFULL-5353 Add legacy MonitoredCollectionDaoEhcache implementation
OBMFULL-5353 Add legacy SyncedCollectionDaoEhcache implementation
OBMFULL-5353 Add legacy UnsynchronizedItemDaoEhcache implementation
OBMFULL-5353 Add legacy SnapshotDaoEhcache implementation
OBMFULL-5353 Add legacy WindowingDaoChunkEhcache implementation
OBMFULL-5353 Add legacy WindowingDaoIndexEhcache implementation
OBMFULL-5353 EhCache migration from 2.4.8 to 2.7.2
OBMFULL-5353 EhCache mustn't be herited when living with two versions
OBMFULL-5353 Migrate EhCache when starting OPush