v1.6.0

Features

• fitter: auto-reduce restarts for small smooth-loss fits (1a61437)
• fitter: wire MADS poll-size floor to tolerance; add lever sweep (90636b9)
• fitter: add MADS optimizer + benchmark vs Nelder-Mead (04a144b)
• venn: add rotated rectangle shape for 4 set venn diagrams (322c1d9)
• web: add rotated rectangles (33b9250)
• shapes: add RotatedRectangle shape with derivative-free fitting (254adbd)