CS fixes
Add Compose button on message view page (#1488747)
Fixed javascript error on extwin message page (classic skin) - removed splitter.
Add unsupported alternative parts to attachments list (#1488870)
Better GD module functions detection, should fix "Call to undefined function imagecreatefromjpeg()" error
Don't display message parts with unsupported text type, e.g. text/calendar
Fix Call to undefined method rcube_db_sqlite::_get_result()
Fix version comparisons with -stable suffix (#1488876)
Fix locking issue in SQLite driver (#1488874)
CS fixes
Fix comment
Add notes about new requirements of the new mysql database driver,
add check in installer (#1488875)
Small optimization
Don't force 'stop' action on last rule in a script
Update changelog, set version to 6.1
Add warning in default_host description, so after change update of users table is needed (#1486386)
Add hint about possible disabled fsockopen() function on connection error
Treat image/pjpeg as image/jpeg
Make html button-links work in IE
Merge branch 'master' of github.com:roundcube/roundcubemail
Fix handling of parentheses in URLs