Fix for bounding box used for interpolation

The bounding box for deformed elements was based on looping over quadrature points, however in general quadrature points might not include vertexes! Examples include Gauss or Radau points. This solves #154 (closed).

Additionally the nearest point selection has been enabled to cover edge cases in which a point lies outside an element. Note that this can happen either if the new point is outside the original domain or if it lies on the boundary between 2 elements and the tolerance in v_ContainsPoint is too tight.

Two regression tests have been added.