Version bumped to 5.5.16 by buildsystem.
Version bumped to 5.5.17 by buildsystem.
Installer [win32]: Fixed some duplicate identifiers.
Version bumped to 5.5.18 by buildsystem.
Installer [win32]: More fixes to detect MariaDB.

The main problem this time was that WIX-identifiers are case sensitive,
and that both the identifiers "MariaDB100Location" and "Mariadb100Location"
existed, with the latter not having the correct value.
Version bumped to 5.5.19 by buildsystem.