Fix #1317 Enhance email template
Merge pull request #550 from nlegoff/template_mail

[3.8] Fix #1317 Enhance email template
Allow thumbnail extraction configuration
Fix error message
Bump to php-exiftool 0.3.0
Merge pull request #552 from romainneutron/thumbnail-generation

[3.8] Thumbnail generation
Merge pull request #553 from romainneutron/dependencies

[3.8] Bump to php-exiftool 0.3.0
Merge branch '3.8'