Merge pull request thephpleague#182 from vansanblch/patch-1

Update slim.md

Add webp to docs

Merge pull request thephpleague#221 from BlueBayTravel/flip-manipulator

Flip manipulator

Merge pull request thephpleague#194 from jasonvarga/master

Save pjpg as jpg when including file extensions

Merge two similar tests.

Merge pull request thephpleague#126 from bonzai/feature/watermark-opa…

…city

Add ability to set the opacity of the watermark

Fix progressive jpeg encoding.

Update lock file for new version.

Merge pull request thephpleague#137 from jackmu95/rewind-error-fix

Make sure stream is seekable before using `rewind()`

Add support for Symfony 3.x components.