Merge branch 'hotfix/1.4.7'
Update ProductCallbacks.php

Typo in #421
Require "contao/core" instead of non existing package "contao".
Only replace contao-legacy/isotope in self.version.
Starting 1.4.8 hotfix branch
Merge branch 'master' of https://github.com/tristanlins/core into hotfix/1.4.8
Improved composer.json
Merge branch 'patch-1' of https://github.com/joke1/core into hotfix/1.4.8
Fixed edge case SQL issue in rules module (#771)
Load language files to get labels (#841)
A 404 page should always be generated if the product cannot be found (#763)
Generate 404 if no alias is given for the product reader (#763)
Group by product ID, otherwise we would get a result set for each category
The cache returned a Model\Collection instead of an array (#843)
Do not import into the class
Generated PDF did not search the shop config folder in the back end (#534)
Recursively create upload directories (#837)
FineUploader can only show the first warning
Show uploader error messages in widget
CS