Merge branch 'master' of D:\Documents\GitHub\sketchup-shapes
Last code format/style tidy-up - removed brackets round a few if() statements, renamed variables to less cryptic names
Added Helix shape, based on previous DrawHelix14.rb by Jim Foltz, in turn adapted from DrawHelix13.rb by Peter Brown 4/8/2004
Works to draw, and remembers previous parameters, but isn't editable (doesn't yet use mesh_additions.rb to draw the helix)
Still to do: use mesh_additions; allow left hand as well as right hand screw shape
Now draws in container (not model), so shape is editable with R-click. Allows negative values for pitch (helix goes down) and/or rotation (negative draws left hand helix)
Added angle at which to start drawing helix, as another editable parameter
Edited file comments in su_shapes.rb/shapes.rb and su_shapes.rb to reflect latest code changes, and added Helix shape to CHANGELOG.md
Minor change to starting default number of segments per rotation for helix - from 12 to 16 to match other circle-based shapes
Merge branch 'johnwmcc-master' into upstream-master

Conflicts:
	src/su_shapes.rb
Merge pull request #21 from thomthom/upstream-master

Resolved merge conflict with johnwmcc's latest pull request.