Information about salary expense of department was added
* Use case about employees sorting was added
* Department's stored procedure's name was changed
* Employee search and sort classes was pooled to one "EmployeeService"
* Unnecessary exception's throwing was removed
* Edit employee placeholder was changed
* Code duplication was removed
* Unnecessary object creation was removed
* Names of methods were clarified (SelectSalaryInformationDao class)
Departments sort option was added
* Department's jsp was changed
* Department to employee linker was moved to EmployeeService class
Merge branch 'sortDepartmentsFeature' into salaryExpenseOfDepartmentFeature
Merge branch 'salaryExpenseOfDepartmentFeature' into sortByProfessionFeature