Comment a bit of code that confused me
DiffPhysics::nonlocal_ functions

Also add some helper code for refactoring, update outdated comments
Add DiffContext::nonlocal_reinit()

And FEMContext::has_elem()
Enable DofMap::dof_indices on NULL Elem

This is now useful for getting just the indices of SCALAR dofs.
Add TimeSolver::nonlocal_residual()

And add implementations, and refactor the hell out of foo_residual()
to keep those implementations simple.
Assemble nonlocal residual/jacobian contributions
Don't bother futzing with an empty element system

This is probably a trivial improvment to efficiency in opt mode, but
more importantly it fixes some regressions in devel mode.
Restore variable number ordering for SCALAR dofs

Putting them out of order was screwing up FEMContext initialization,
and I'd prefer to make this code less complicated rather than make
that code more complicated.

Hopefully nobody else has hard coded the previous wacky ordering into
their applications...
Fix DEBUG-mode segfault

When using the new "call dof_indices with elem=NULL" behavior,
dof_indices really can't dereference elem...
Don't forget to add the nonlocal residual!
Fix default nonlocal_mass_residual

TimeSolvers are going to use elem_solution to store time derivatives
so we can't just pull scalars directly from current_solution()
#include <sstream> // std::istringstream
Added access to variable names
Let sideset inherit name of nodeset when calling build_side_list_from_node_list().
Misc. improvements to Abaqus reader

* Support reading T3D2 (truss) and S3R (three node large strain triangular shell element)
* Associate nodeset, sideset, and elset names with their respective IDs.
* Delete whitespace characters, including newlines, when extracting labels.
* Handle reading multiple *NODE sections.
* Don't set the mesh dimension based on elements seen, instead set the
  proper flags in the elems_of_dimension vector.
* Add the max_elem_dimension_seen() function and use it to set the
  Mesh dimension. This function should probably be moved to the
  MeshOutput base class.
Support reading lower-dimensional elements for BCs

* Use a multimap to assign assign sideset ids.
* Skip assigning subdomain ids to lower-dimensional elements.
* Delete lower-dimensional elements in Abaqus reader.
* Associate sideset name with ID.
Read and store NSET names while reading *NODE sections.
Skip reading *NODE and *ELEMENT OUTPUT sections.
Deleting print/debugging statements.
Merge pull request #304 from aeslaughter/exodus_vars

Added access to variable names in ExodusII reader