• Added web UI undo and redo.
• Added a History menu to the web UI's top bar for turning on undo (disabled by default), moved the console button to a tab on the left side.
• Added new cell shapes to the -grid command: triangle, triangle2, rhombus, rhombus2, square2.
• Added cell-scale= option to -grid. Takes a value between 0 and 2 for scaling each grid cell shape.