Kite dihedral - parametric (customizer)

A parametric dihedral, useful as a replacement part or for building your own kite. The dimensions (i.e. 7.5mm) in the STL file names refer to the spar diameter for which it's intended; holes have been sized to fit such a spar, accounting for expected levels of hole shrinkage due to the printing process. The arm length, spine length and hole sizes can all be adjusted using Customizer; the spine and arm holes can be configured independently in case you're using a different diameter of spar for t