Created entity Comment.
Defined CommentManager interface and initialization of CommentManagerImpl.
Defined exceptions for invoking errors when entity is being persisted.
Added Hibernate search dependencies to pom.xml

Signed-off-by: Radek.Koubsky <radekkoubsky@gmail.com>
Merge branch 'master' of https://github.com/halafi/pv243-music-manager.git

Conflicts:
	music-manager/pom.xml

Signed-off-by: Radek.Koubsky <radekkoubsky@gmail.com>