Add Snipes to Steelwork Members

Creates and modifies snipes on support structural members. A snipe is a cut angle on the support structural member, such that a corner is removed.

This feature currently only works with angular support structural members. For example, steelwork profiles of type GENSEC and gtype ANG. Two cases are catered for:

• Snipe on end of leg attached to stiffener

• Snipe on free end of support structural member.