Merge branch 'release/2.23' into develop
preserve timer upon update
use notification ids
progress in toasts
use isClickable for non-clickable notifications
handle disabled notifications
use CSS to hide notification elements
notifications refactored
review
jshint errors
build/dev with gulp
imagemin
uglify sourcemaps bug workaround
hide panel hint when panel is not selected
filter for look&feel, linked filters
jshint issues
improved release process
improvements, stability
#107: link ratings hint adjusted, prevent-reset improved
small improvements