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 'omit-getObserverClass' into develop
Merge branch 'develop'
Merge pull request #53 from TheKojuEffect/master

Omit the need to define getObserverClass() in EntityModel
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