CompanyDaoImpl : add of list() method
ComputerDaoImpl : fixing of insert() method about company.getId() if
company is null
DaoException : created for try catch in DaoImpl
DaoUtils : fixing of silentClosing because no test if is null
ICompanyDao, CompanyDao : findById(), list()
Company : add toString() method
Computer : change Integer companyId to Company company
computers.jsp : use headerMenu.tag for sorting
headerMenu.tag : taglib for column sorting
AForm : abstract class for all forms
AddComputerForm : the instert form
FormUtils : util methods for all forms
FormValidationException : exception for form
ICompanyService, CompanyServiceImpl : findById(), list()
AddComputerController : servlet to add a computer
addComputer.jsp : view to add a computer
stylesheets.jsp : contains links to the css -> need to be imported