Use a proper version constraint
Guzzle 5
PSR-4
Merge pull request #16 from GrahamCampbell/patch-3

PSR-4
Merge pull request #15 from GrahamCampbell/patch-2

Upgrade to Guzzle 5
Merge pull request #14 from GrahamCampbell/patch-1

Use a proper version constraint for symfony classloader
remove pio_ prefix in entity types and property names
remove pio_ prefix in readme
Merge branch 'develop'