Revert "Make autoloading of the framework classes work from any location".
Allow loading rcube_* classes from other locations (for e.g. managesieve plugin).

This reverts commit e4394c95e0a39607f4fdbd427b249b1e611ca0ff.
Fix typo in DB version strings (there should be no .sql suffix)
Add workaround for invalid message charset detection by IMAP servers (#1488968)