* develop-ascraeus:
[prep-release-3.1.0-RC4] Update phpBB Version for RC4 development
[prep-release-3.1.0-RC4] Add changelog for 3.1.0-RC4
[prep-release-3.1.0-RC4] Prepare Changelog
[prep-release-3.1.0-RC4] Add migration for 3.1.0-RC4
[prep-release-3.1.0-RC4] Update version to 3.1.0-RC4
Conflicts:
build/build.xml
phpBB/includes/constants.php
phpBB/install/schemas/schema_data.sql
phpBB/styles/prosilver/style.cfg
phpBB/styles/subsilver2/style.cfg