Removed some unnecessary filed; Added the icons for the plugins and repositories; Started with a log for the current controller

Updates the themes; Replaced the header from the login-page; Removed the alternating row-colors to avoid problems with other themes

Updated the Kieker logo to a correct version; Reorganized some of the menus, including the icons; Set the message-components to 'sticky'; Made the data table in the overview selectable

Started with an improved version of the GUI, including a multi user mode; Updated also the Kieker-jar.