Check if file exists when generate thumbnails
Fix #400, Fix #402, Fix deletion of File type
Update composer.json
Merge pull request #462 from Prims47/check-file-existence

Check if file exists when generate thumbnails
Fix #464, Fix #180, update the documentation to explain how to use the LiipImageBundle
Fix typo
Fix #393, by adding try catch and log issues
Merge branch 'sonata/master'

Conflicts:
	composer.json