First implementation of SQL validator
Implementation of update and replace methods SQL
Updated SQL tests for post and put
Added date time to SQLAlchemy type mapping
Added serialiser to SQL data layer and bug fixing
Improved validation for post requests
Fixed tests for put and post
Removed default from common SQL columns

Removed the default and on update values from the SQL common columns,
let eve take care of that. Fixed a possible bug with eve methods
date_created and last_updated common methods
Fixed bugs with SQLAResult structure
Fixed tests bug and added patch tests
General clean up
Removed skip from patch test
Removed old test
Merge pull request #326 from dedalusj/sqlalchemy

Finished implementing main methods for SQL extension