Create User RESTful Web Service that response on JSON.
Create JSONBuilder class that serialize classes to JSONOblects.
Add Jersey and Gson jar's.
mergin branches
Merge branch 'chemodurov' into webservice

Conflicts:
	BuyIt/WebApp/WEB-INF/web.xml
	BuyIt/build/classes/com/epam/lab/buyit/model/Product.class
	BuyIt/src/main/java/com/epam/lab/buyit/model/Product.java

Update UserWebService, JSONBuilder, implement getItemById 
in UserServiceImpl, create UserSerializationAdapter
Create UserSerializationAdapter