Upgrade Existing WebApp for Math Operations (Drag & Drop Boxes and Arrows)

I have a software (written in HTML, Javaascript and PHP) with a current functionality described in [login to view URL] I need the following upgrades: A. New look and feel, more buttons, tabs, minor functionality upgrades B. 'Sensitivity Analysis' functionality C. 'Monte Carlo Analysis' functionality - use the library at [login to view URL] I have described everything in [login to view URL], except the following items within the upgrade "A": 1. Boxes should be resizeable 2. Box properties should show the colour and properties that have been previously assigned to it (currently it shows previous edits to other boxes) 3. Arrow head should be at the end, not in the middle 4. Fit to screen button (on the side bar) - fits the tree to the canvas size 5. New, Open, Save, Save As, Close functionality as explained in the video 6. Files should be saved to the desktop as XML, JSON or similar (with tree information - boxes and connections, values, formats and colours) 7. Undo/ Redo function 8. Variables appear in the box properties when arrows are connected - so that we can construct the formula easily 9. Duplicate version of the software with minor changes. Screen should look as shown in the picture (link below) - please see the notes under Monte Carlo button in the pic [login to view URL]