fix handling of legacy database.sql multicolumn keys in dca extractor
Added sendNewsletter hook
Add support for `.woff2` files (see #7301)
Preserve the original CSS ID and classes in the alias elements (see #6638)
Use the database driver to change the database collation (see #7302)
Unset the new `origtype` field in the database installer
Optionally hide files without matching meta data in downloads (see #6874)
Add a regex to check for nonnegative natural numbers (see #4392)
Adjust the file deletion message (see #6945)
Support the `backlink` configuration setting in the parent view (see #7083)
Merge branch 'master' of https://github.com/backbone87/contao-core into develop
Fix a coding style issue
Download the translations during the build process
Add the "title" attribute to the `link_open` insert tag (see #7195)
Hide the "start" and "stop" fields if an element is not published (see #7148)
Prevent timing attacks when verifying passwords (see #7115, #5853)
Use `CRYPT_BLOWFISH` as preferred hash algorithm (see #5853)

This effectively raises the minimum PHP version to 5.3.7, because the Blowfish modes that deal with potential high-bit attacks have only been added in this version.
Limit the selectable file types depending on the element type (see #7003)
Fix the new password hash functions as pointed out by @ausi
Make the pagination template more flexible (see #7174)