Mesh Tool 1.0.4 Update

* Add Draw Circle

* Add Insert Edge loop

* Add button to force rebuild mesh distance fields

1.0.4 Change Log:

• Add Draw Circle
• Add Insert Edge loop
• Add Delete Vertices
• Add Delete Edges
• Add button to force rebuild mesh distance fields
• Add Normal as new Local Transform Coord option;
• Improve De-select Edge by Alt key, now can de-select shared edge from other side
• Fix Bug when LocalTransformCoord set to world, cached transform not been updated