Fix bug with not having FaceMaterials inited on boundaries unless a BC was active
closes #3586
Hardening added to WeakPlaneTensile.

Three nice tests added.

Also, FiniteStrainPlasticBase now provides a Material which is
the number of Newton-Raphson iterations used.  This is useful for
debugging, but also i think it'll be useful in the future when
we have to apply the strain increment in small amounts in order
to return to the yield surface for very nonlinear models.

Fixes #3625
Automatically set pc_hypre_boomeramg_strong_threshold to 0.7 for 3D meshes
closes #3245
Merge pull request #3618 from permcody/elem_aux_boundary_3586

Fix bug with not having FaceMaterials inited on boundaries unless a BC w...
Override the automatic adjustment of the strong threshold few a few sensitive tests
Merge pull request #3628 from WilkAndy/wpt_hard_3625

Hardening added to WeakPlaneTensile.
Merge pull request #3630 from permcody/hypre_threshold_3245

Automatically set pc_hypre_boomeramg_strong_threshold to 0.7 for 3D mesh...
Fix a bad optimization refs #3586
Re-factored SolutionUserObject to correct variable numerbing mismatching problem with MeshFunction
(closes #3517)