fixing bugs (entity manager in abstract dao cannot be static), refactoring
Merge branch 'master' of https://github.com/jirikrepl/PA165-Manager-LEGO-stavebnic

Conflicts:
	src/main/java/cz/muni/fi/PA165/dao/AbstractDao.java
	src/main/java/cz/muni/fi/PA165/dao/CategoryDao.java
	src/main/java/cz/muni/fi/PA165/dao/ThemeSetDao.java
	src/main/java/cz/muni/fi/PA165/dao/ThemeSetDaoImpl.java
	src/main/java/cz/muni/fi/PA165/daoInterface/BrickDaoInterface.java
	src/main/java/cz/muni/fi/PA165/daoInterface/BuildingKitDaoInterface.java
	src/main/java/cz/muni/fi/PA165/daoInterface/CategoryDaoInterface.java
	src/main/java/cz/muni/fi/PA165/daoInterface/DaoInterface.java