Add User Creator, Validator for input Data for RegistrationServlet 
Add error404 page
Change registration servlet and jsp files
AJAX login verification
Implement UserDAO getUser by login and password and verifyLogin.
Create CheckLoginServlet and login-check.js
Update registration.jsp
Delete builds
registration successed
Add gitignore
Merge remote-tracking branch 'origin/master' into aleg

Conflicts:
	BuyIt/WebApp/WEB-INF/web.xml
	BuyIt/WebApp/jsp/registration.jsp
	
Login Servlet
Delete builds add gitignore
Update UserWebService (authentication), create web-services.properties
Update UserWebService (loginUser)
login
Converted ProductDAO,CategoryDAO,SubCategoryDAO.
Add ProductService,CategoryService,SubCategoryService.
All methods tested.
Merge chemodurov branch with Alegos.
Create category_viewer.jsp, item_preview.jsp and CategoryServlet
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
registration tooltip
tip.js
Logout and changes in navbar
Create CategoryControllerServlet, update CategoryServlet,
SubCategoryService, item_preview.jsp, category_viewer.jsp, web.xml
Merge with aleg