Allow minimizing the main dialog, only 'close' to the sys tray if the dialog is closed or the hide-button is clicked.
(Fixes issue #332) : Minimizing will minimize to system tray and lose the current filter
Check for empty project name and show an error balloon/messagebox if it's empty.
(Fixes issue #334) : Creating a new project with just some random text as "URL to monitor" creates a new empty project.