mv n-b_ext1-basic to basic1, create sterling

* Moved all files for nerf-barrel_extension1-basic-* to "basic1/"
* Created sterling/ with initial .scad and added some reference material:  pictures and diagrams with measurements.

	new file:   basic1/nerf-barrel_extension1-basic-100mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-105mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-120mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-140mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-147mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-160mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-165mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-180mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-200mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-30mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-60mm_length.stl
	new file:   basic1/nerf-barrel_extension1-basic-80mm_length.stl
	new file:   basic1/nerf-barrel_extension1-test1.gcode
	new file:   basic1/nerf-barrel_extension1-test1.stl
	new file:   basic1/nerf-barrel_extension1.scad
	new file:   sterling/Barrel-m,easure.jpg
	new file:   sterling/Barrel.jpg
	new file:   sterling/Barrelbigend.jpg
	new file:   sterling/Business20End20after_zps856b70c4.jpg
	new file:   sterling/Picture56.png
	new file:   sterling/Picture58.png
	new file:   sterling/Picture59.png
	new file:   sterling/Picture63.png
	new file:   sterling/Picture64.png
	new file:   sterling/Picture7-3.png
	new file:   sterling/Picture72.png
	new file:   sterling/Picture74.png
	new file:   sterling/SL2A3 DWG.JPG
	new file:   sterling/SterlingTube1.jpg
	new file:   sterling/SterlingTube2.jpg
	new file:   sterling/barrellength.jpg
	new file:   sterling/dscf0910z.jpg
	new file:   sterling/nerf-barrel2-sterling.scad
	new file:   sterling/sectionalized-sterling-smg-sn-679-2-7606-p.jpg
	new file:   sterling/sectionalized-sterling-smg-sn-679-3-7606-p.jpg
	new file:   sterling/sectionalized-sterling-smg-sn-679-7606-p.jpg
	deleted:    nerf-barrel_extension1-basic-100mm_length.stl
	deleted:    nerf-barrel_extension1-basic-105mm_length.stl
	deleted:    nerf-barrel_extension1-basic-120mm_length.stl
	deleted:    nerf-barrel_extension1-basic-140mm_length.stl
	deleted:    nerf-barrel_extension1-basic-147mm_length.stl
	deleted:    nerf-barrel_extension1-basic-160mm_length.stl
	deleted:    nerf-barrel_extension1-basic-165mm_length.stl
	deleted:    nerf-barrel_extension1-basic-180mm_length.stl
	deleted:    nerf-barrel_extension1-basic-200mm_length.stl
	deleted:    nerf-barrel_extension1-basic-30mm_length.stl
	deleted:    nerf-barrel_extension1-basic-60mm_length.stl
	deleted:    nerf-barrel_extension1-basic-80mm_length.stl
	deleted:    nerf-barrel_extension1-test1.gcode
	deleted:    nerf-barrel_extension1-test1.stl
	deleted:    nerf-barrel_extension1.scad