Merge pull request #12 from vania-pooh/master

Fixed issue with mime type
Merge pull request #13 from vania-pooh/master

Downgraded to 2.3.x series of symfony/http-foundation
step support trait - return closure result to caller
Merge pull request #15 from Djamiyo/step-support-extension

step support trait - return closure result to caller
Added @Issue annotation support (fixes #16)