Converted ProductDAO,CategoryDAO,SubCategoryDAO.
Add ProductService,CategoryService,SubCategoryService.
All methods tested.
Merge remote-tracking branch 'origin/master' into cehmodurov
Update category_viewer.jsp, item_preview.jsp, HomePageServlet, 
CategoryServlet and some DAO's and Services
Create DescriptionDAO and DescriptionService
Create CategoryControllerServlet, update CategoryServlet,
SubCategoryService, item_preview.jsp, category_viewer.jsp, web.xml