Line2: Consistency: Vec2 constructor now copies args
Added new icons; removed old ones
IconEnum: Added cancel icon
EditorMenuBar: Added delete
ToolContextual: Added delete(), selectUnderlying()
ToolManager: Added delete()
Selection: Added debug output on delete()
Actions: Added getDeleteAction()
EditorCreator: Linked delete action
GraphicTrace: Now shows highlight/select visibly
ToolTraceDrawer: Now shows hints; traces can be terminated by ctrl+LMB
LineDDA: Fixed typo/bug causing incorrect values on negative Y axis
Post-debug cleanup