Loosen sebastian/diff requirement
minor #555 Loosen sebastian/diff requirement (GrahamCampbell)

This PR was merged into the 1.0.x-dev branch.

Discussion
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Loosen sebastian/diff requirement

This allows people to use the upcoming 1.2 release of sebastian/diff.

Commits
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5d20f51 Loosen sebastian/diff requirement
Merge branch 'master' of git://github.com/fabpot/PHP-CS-Fixer