Create EntityController interface

OPEN - task 51: Create CRUD packages for Product entity 
http://github.com/DevOpsDistilled/OpERP/issues/issue/51
Create ProductController extending EntityController

OPEN - task 51: Create CRUD packages for Product entity 
http://github.com/DevOpsDistilled/OpERP/issues/issue/51
Create bare CreateProductPane

OPEN - task 51: Create CRUD packages for Product entity 
http://github.com/DevOpsDistilled/OpERP/issues/issue/51
Define getObserverClass in itself

Doesn't not require extending classes to implement getObserverClass
Add test to test getObserverClass()
Change getObserverClass access modifier to protected
Change test due to change in access modifier

protected method getObserverClass() can't be called from inside test, so
commented out.
Remove getObserverService() definition

Not required due to implementation in subclass
Merge branch 'develop' into iss52-category-crud
Rename EntityObserver to EntityModelObserver

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Rename package name

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Export CategoryService

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Annotate with @Service

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Create CategoryService ProxyBean

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Rename EntityObserver to EntityModelObserver

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Omit the need to send ID for generics implementation

Used wildcard(?)
Previously written code was reduntant as ID is declared in Service as
well as in Model declaration

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
@Bean CategoryModel

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
@Bean CategoryController

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
@Bean for CreateCategoryPane

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54
Add "create category" button

OPEN - task 54: Create Category CRUD packages 
http://github.com/DevOpsDistilled/OpERP/issues/issue/54