Update the links to contao.org and the copyright notice

Signed-off-by: xchs <github@gmx.net>
Merge branch 'hotfix/update-links' of git://github.com/xchs/contao-check into develop
Update all language files
Add the version 3.1.0 file hashes
Merge branch 'develop'
Make the install and validate links buttons (see #46)
Update all language files
Merge branch 'develop'
Add the Contao 3.1.1 file hashes
Merge branch 'develop'
Add the version 2.11.12 file hashes
Add the version 3.1.2 file hashes
Add 770 as valid directory permission setting (see #49)
Use the new download URL (see #52)
Use the new download URL (see #52)
Use `type -p` instead of `which` (see #6128)
Add the version 3.1.3 file hashes
Use `command -v` instead of `type -p` (see #6128)
Add the version 3.1.4 file hashes
Add extended shell availability checks (see #23)