v1.1.1: Add compatibility with Symfony/process 3.0

This release adds compatibility with Symfony/process 3.0 (backwards compatibility is maintained)

v1.1.0: Add compatibility with Symfony3

Merge pull request #10 from marc-casoliva/patch-1

Remove deprecation messages for unquoted vars

v1.0.3: Merge pull request #9 from GijsL/master

Removed deprecations for Symfony 2.8