Collision detection for quadrilateral and hexahedral cells

[Ivan Yashchuk]

Collision detection for quadrilateral and hexahedral cells is not implemented.

See https://bitbucket.org/fenics-project/dolfin/pull-requests/385

Following code will throw an error:

from dolfin import *
mesh = UnitQuadMesh.create(3, 3)
V = FunctionSpace(mesh, "P", 1)
u = Function(V)
u(0.5, 0.5)