Fixed entity validation
Fixed test case for entity validation
Added throws in docblock
Fixed test case for entity validation
Fixed test cases for push method
Fixed docblock text
Removed entity validation of message item
Removed test case of message item
Fixed entity validation of message item. Remove entity validation of message item in removeMessages method.
Fixed test cases for push method
Merge pull request #2 from yuslielg/issue-1

Improved validation of input parameters (fix #1)
Added phpunit as dev requirement. Upgraded dependencies
Removed entities and interfaces in favor of abstract models
Fixed typo in license file
Fixed some typos. Replaced EntityManagerInterface by EntityManager to get access to "find" functions
Removed sample from readme
Fixed typo