Time SNES solve
Remove timing specialised mesh building functions
minor doc fixes
Fix for issue #336 (incorrect ndofs for interior face loop)

Fix proposed by Lawrence: multiply number of dofs by two for interior facets.
remove superfluous dot(...) with scalar-valued quantities
Merge pull request #335 from firedrakeproject/test_steady_adv_fixes

remove superfluous dot(...) with scalar-valued quantities
remove exterior_facet_topbottom code (expanded at the UFL level)
Merge pull request #329 from firedrakeproject/remove_topbottom

remove exterior_facet_topbottom code (expanded at the UFL level)
paraview output -- check for OPC, not OPE
Merge pull request #334 from firedrakeproject/paraview_ext_fixes

paraview output -- check for OPC, not OPE
add CircleManifoldMesh (gdim 2, tdim 1)
add non-extruded circumference tests
add radial-extrusion-of-circle test
add poisson test
prettify jacobian snippets
Merge pull request #339 from firedrakeproject/prettify_snippets

prettify jacobian snippets
Merge pull request #337 from firedrakeproject/fix_ndof_inparloop_over_interior_facets

* fix_ndof_inparloop_over_interior_facets:
  Fix for issue #336 (incorrect ndofs for interior face loop)
Merge pull request #331 from firedrakeproject/circle_surface_mesh

* circle_surface_mesh:
  add poisson test
  add radial-extrusion-of-circle test
  add non-extruded circumference tests
  add CircleManifoldMesh (gdim 2, tdim 1)
Add extrusion documentation
Add introduction