Mesh Tool - A Mesh Editor

Hi Wolfen, glad it get it working!

Regarding your questions:
Set Pivot: That’s something I’m working on, will be in next 1.0.7 update (you can track it here: Set Mesh Pivot to Current Transform Widget Pivot · Issue #25 · marynate/mesh-tool · GitHub)
UV Window: Custom UV editing is the feature I want to have but haven’t get time to really start working on. I would like to start working on it after wrapping
up current planned features (mainly slab transform and blueprint based mesh building). Meanwhile you can try Auto UV (as mentioned or the Texture Mapping tools under Texture Map category)
New mesh from scratch: Insert Mesh with “Replace Mesh” option checked will basically give you new fresh mesh to work on. But form UX pov, I guess a new “New Mesh” button will make more sense. Will add that.