LWCAD 5.1 new features

LWCAD 5.1 new features

Interactive Mode - new interactive mode for Rectangle,Circle,Arc and derived tools

Pivot Handle - new behavior of Vector Clone, Move Snap tools

Angle Tool - new behavior of Angle and Rotate Snap tools

Arc Tool - new spiral mode and spring mode (using depth)

Radial Clone - new spiral mode

Array Clone - new rotate handle

- new Show Handles and Show Buttons option

Ucs Grid - reverted back to three modes: OFF,LW,UCS

Fence - simplified into two library types: fence and column, no presets

- new start-end column buttons

- new TAN button

Round - updated to round edge of closed NURBS surfaces