Handle multiple projects more easily

[freywald]

1. Menu->Open Project always replaces the current project. There should be a way to open a project in a new window. A new menu item "Open Project in new Window" would suffice.

2. On application close, KIT should remember all opened projects. After starting the program again, KIT should have a button "restore previously opened projects", situated below "+ create project" and "|O| open project". Maybe also a checkbox there "auto restore previously opened projects" which will be active on next run.

3. A new menu item, "exit application" will close all opened projects [windows] and exit the application. As before, once a script needs to be saved, KIT should ask. Better: don't ask for each script (modal dialog nightmare), instead, show a single window containing summary of changed projects, use check boxes before the project name, the users clicks on the checkboxes, finally below, a button "save selected projects and exit application" and "don't exit application yet". The user does not have to select any checkboxes to use the first button.

Note: currently I open multiple instances of KIT to work around it. I'd like to execute KIT only once and open several scripts through the same instance. See PHP-Storm. KIT could also go the tab approach, but IMHO multi window is much better, since projects are not inter-depended.

Thanks for reading my lousily written request.