New actions
Copy/paste ok
Delete ok
Added filename member in Diagram
Added license
Save and save as actions
using windowModified
Implementing open/save
File format
Completed opening/saving to msketch
Window title showing filename
Removed replaceSpaces function
.msketch file format description
Fixed actions in menu bar
Trying to implement context menus
Removed context menus
Fixed node id setting
Created class for History
Default settings for history
Defined data structures