#JC-1494 Added column LAST_READ_POST_DATE to the LAST_READ_POST table (migration +  Hibernate mappings)
#JC-1494 Fixed unit tests, changed the markAllRead method of the LastReadPostHibernateDao class - now it works with both last index and last date
#JC-1494 Removed usages of the setPostIndex method
#JC-1494 Changed lastReadPostIndex to lastReadPostDate in the Topic class
#JC-1494 Removed usages of the getPostIndex and setPostIndex methods in the Java code (they still present in the hibernate queries). Fixed migration - removed "not null" constraint for the LAST_READ_POST_INDEX column
#JC-1494 Changed COUNT_POSTS_TOPICS_VIEW to work with the date instead of post indexes
#JC-1494 Deleted the postIndex field from the LastReadPost
#JC-1494 Added sorting order for Posts list for Topic
#JC-1494 Fixed after code review
Merge remote-tracking branch 'origin/JC-1494'

Conflicts:
	jcommune-service/src/main/java/org/jtalks/jcommune/service/transactional/TransactionalPostService.java