Removing instances of Elk namespace.

Refs #2936.
The MOOSE unit tests now depend on the solid mechanics module.

Refs #2936.
Removed uniform refinement limit (#1189)
Merge pull request #3067 from jwpeterson/remove_elk

Remove Elk namespace and mentions of Elk in documentation
Merge pull request #3068 from aeslaughter/material_output-1189

Removed uniform refinement limit