Port initial AbstractMapper and AbstractEntity from Kohana implementation.
Create table gateway factory so table gateways can be created in the abstract mapper rather than the mapper service definition.
Correct method calls in Stdlib\Arr.
Use Zend Select object instead of TableGateway for building queries.

Fix Abstract Mapper to use the Select and Sql objects to build queries.
Implement insert and update functions using Zend Db query builder.
Implement delete method.

Extract execute method to remain DRY.
Add DocBlocks.

Simplify the persist method.
Remove validation and rules.
Add missing DocBlocks.

Remove check for rules.
Use Sql object instead of raw Sql\* objects to build queries.

Add missing DocBlocks.
Merge pull request #10 from synapsestudios/mappers-entities

Mappers and Entities