Merge branch 'ht/approx'

Merge branch 'ht/approx'

* ht/approx: (65 commits)
  Polytop distance tester: Export problem as input to active set QP tester.
  Minor spelling correction in source comment.
  Example: Updating to use info.other field in path-to-path approximation.
  New example: Systematic testing of intersection (and approximation) algorithm(s).
  Intersection and approximation: Using "info" field to point on second path (and distance).
  Doc: Informing about the use of the new "info" field.
  Doc infrastructure: Supporting field tables outside type doc.
  Introducing the "info" field in sliders.
  Doc: Showing how approximation can be used instead of intersection in tutorial.
  Bugifx: StructureFactory was sorting fields by pointer value rather than lexically.
  Whitespace fixes.
  Doc: Minor spelling correction.
  Polytope distance tester: Command line setting of two more tolerance parameters.
  Bugfix: Maximum number of iterations for polytope distance was too low.
  Clean up: Removing all example data for polytope distance computation.
  Doc: Describing path-to-path approximation in the tutorial, including an example.
  Polytope distance: Using the new distance tolerance for (scaled) Lagrange multipliers.
  Removing debug prints.
  Bugfix: Default value for singular value tolerance should be 1e-3, not 1e-14.
  Polytope distance: New interpretation of Lagrange multipliers.
  ...

Conflicts:
	doc/parts/algo-tol/index.sxml