Merge pull request #20 from symphonycms/integration

Integration
Merge pull request #23 from symphonycms/integration

Release Version 2.1.0
version 2.1
Merge pull request #24 from DeuxHuitHuit/2.1

Version 2.1
Merge branch 'integration'
Abstract format transformers to seperate classes. Fix an error where the initial creation of a data source would generate an invalid cache result