Define ApplicationModel i.e ProductModel for Product Entity

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Declare Observer for ProductModel

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Declare Observer for BrandModel

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Define getService() method

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Define BrandModel

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Remove "Item ID" inputs and rearrange UI

OPEN - task 32: Add "Create Item" functionalities 
http://github.com/DevOpsDistilled/OpERP/issues/issue/32
Make EntityObserver non-generic interface

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Update these Observers according to changes to EntityObserver

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Use non-generic EntityModel

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Add abstract getObserverClass() and use it for dynamic updateMethods()
invocation

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33

updateMethods() are methods in EntityObservers like "updateItems(List)"
Implement getObserverClass()

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Remove obsolete updateAll() method from Observer

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Create @Bean for ProductModel and BrandModel

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Implement updateMethods and rearrange UI.

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Add BrandModel and ProductModel as Models

OPEN - task 33: Problem with EntityModelObserver architecture 
http://github.com/DevOpsDistilled/OpERP/issues/issue/33
Merge branch 'iss33-change-arch' into develop
Remove @Override findAll() definition

Seed data creation code will be transferred to test branches