update to 3.0

docs/lib3x-archimedean_spiral_extrude.md

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+# archimedean_spiral_extrude
+
+Extrudes a 2D shape along the path of an archimedean spiral. 
+
+When using this module, you should use points to represent the 2D shape. If your 2D shape is not solid, indexes of triangles are required. See [sweep](https://openhome.cc/eGossip/OpenSCAD/lib3x-sweep.html) for details.
+
+## Parameters
+
+- `shape_pts` : A list of points represent a shape. See the example below.
+- `arm_distance`, `init_angle`, `point_distance`, `num_of_points` and `rt_dir` : See [archimedean_spiral](https://openhome.cc/eGossip/OpenSCAD/lib3x-archimedean_spiral.html) for details.
+- `twist` : The number of degrees of through which the shape is extruded.
+- `scale` : Scales the 2D shape by this value over the length of the extrusion. Scale can be a scalar or a vector.
+- `triangles` : `"SOLID"` (default), `"HOLLOW"` or user-defined indexes. See [sweep](https://openhome.cc/eGossip/OpenSCAD/lib3x-sweep.html) for details.
+
+## Examples
+    
+	use <archimedean_spiral_extrude.scad>;
+
+	shape_pts = [
+		[5, 0],
+		[5, 4],
+		[4, 4], 
+		[4, 2], 
+		[-4, 2],
+		[-4, 4],
+		[-5, 4],
+		[-5, 0]
+	];
+
+	archimedean_spiral_extrude(
+		shape_pts,
+		arm_distance = 15,  
+		init_angle = 180, 
+		point_distance = 5,
+		num_of_points = 100,
+		scale = [1, 5]
+	);
+
+![archimedean_spiral_extrude](images/lib3x-archimedean_spiral_extrude-1.JPG)
+