Large refactor: Shapes library,

[trbabb]

• in Shape
  • sdf() added to a bunch of shapes
  • project() added to a bunch of shapes
  • intersect(ray) added to a bunch of shapes
  • Inheritance of shapes was made non-virtual
  • Ray now works for N=1 (this benefits 2D Frustum)
  • Fixed project() in Rect (was projecting to corners)
  • Implemented has_concept<Shape, Concept>, which helps with testing
  • Renamed Bounded.h to Concepts.h
• Implement/port GJK tests from old Profile code
• Remove project() from Frustum (for now) because it was wrong
• Fixed a ton of docs, including Dual
• Removed boost in most places
  • ...but remains for iterator_facade
• clip() and project() are now distinct
• Removed Trace.h and Hit.h (and all associated methods)
• LUDecomp
  • emoved awkward PLUDecomposition class
  • linear_solve() changed to solve x in place and pass b in one variable
  • linear_solve() can solve multiple b at once
  • inv()
  • Now avoids some undue copies and transposes
    • Transpose now only happens when src and dst have different layout
  • Now does allocations above an arbitrary threshold
  • Now shares code much better by delegating to a single bare-array impl, and likely reduces bloat
  • linear_solve()
  • Now permutes in place rather than permute-on-copy for b
    • Which requires less memory
    • ...but may be branchy and bad for cache?
• geom::multiply_add()
  • Has been created and instrumented into inv(), det(), Dual
  • Is more accurate
  • With -march=native, is 20x (!!!) faster when running over a flat array.
  • (This should be perftested in a realistic use case)
• Added templated continuity behavior to Dual
• Removed a bunch of crufty/redundant type names (Vec3d, Vec2f, ...)